所属成套资源:人教版数学七年级上册期末计算题1000例附解析
人教版数学七年级上册期末计算题100例附解析(8)
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这是一份人教版数学七年级上册期末计算题100例附解析(8),共37页。试卷主要包含了化简再求值,计算,化简,25);,计算题,利用等式的性质解方程,2=x-8等内容,欢迎下载使用。
人教版数学七年级上册期末计算题100例附解析(8)
1.化简再求值: (a+2b)(2a−b)−(a+2b)2−(a−2b)2 ,其中 a=−13,b=−3
2.计算:
(1)简便计算: 1534×1614
(2)计算: 2a3b2⋅(−3bc2)3÷(−ca2)
(3)先化简再求值: [(3x+2y)(3x−2y)−(x+2y)(5x−2y)]÷4x ,其中x= 12 ,y=2
3.化简:
(1)-(-2 13 )
(2)-(+0.25);
(3)-(-a)
(4)-[-(-2.8)];
(5)-[-(+1)];
(6)-[+(-5)].
4.计算:(-14)-(+15)
5.计算题
(1)49+(-23)+(-35)
(2)19-(-76)-22-(-52)
(3)−1.6+3.2−0.4+1.8
(4)−7+(−5)−(−2) .
6.利用等式的性质解方程:3x+6=31﹣2x.
7.计算: (−3)×56×(−145)×(−14)
8.计算
(1)−3+8−7 ;
(2)23−6×(−3)+2×(−4) ;
(3)(−24)×(13−18−16) ;
(4)(−37)×0.125×(−213)×(−8) ;
9.2(1-2x)=x-8
10.计算:
(1)(﹣16 34 )﹣(﹣10 14 )﹣(+1 12 )
(2)(﹣ 34 )×(﹣1 12 )÷(﹣2 14 )
(3)(﹣2)2×6﹣(﹣2)3÷4
(4)(4a2b﹣5ab2)﹣(3a2b﹣4ab2)
11.先化简,再求值: 12 x﹣2(x﹣ 13 y2)+( 32 x+ 13 y2),其中x,y满足|x﹣6|+(y+2)2=0.
12.先去括号,再合并同类项4a2+2(3ab﹣2a2)﹣(7ab﹣1)
13.计算:(﹣2)3×4﹣(﹣5)÷ 12 .
14.计算:
(1)8﹣(﹣2)﹣(+3)+(﹣1)
(2)(﹣12)÷(+4)﹣(﹣2)×(﹣3)
(3)23−34+112×−24
(4)−33÷−9−−3×−23+−23 .
15.计算:
(1)(14−56+23)×(−24)
(2)−12019+(−2)2÷45+|1−22|
16.解方程
(1)2(2x+1)=10x+7
(2)3-2(x+1)=2(x-3)
17.解方程:
(1)6−2x=3x−4 ;
(2)32[2(x−23)+43]=1
18.化简: (2x2−12+3x)−4(x−x2+12) .
19.解下列各题:
(1)计算: (2−π)0−(−14)−2+(−4)2020×(14)2020
(2)计算:(2a+5)(2a﹣5)﹣4a(a﹣2)
(3)用乘法公式计算:20192-2018×2020
20.合并同类项:4a2+3b2+2ab﹣4a2﹣6b2 .
21.计算:
(1)(-5.5)+(-3.2)-(-2.5)-4.8
(2)-40-28-(-19)+(-24)
(3)(23−112−115)÷(−160)
(4)−14−(1−0.5)×13×[2−(−3)2]
22.计算
(1)(−4)−(+13)+(−5)−(−9)+7
(2)614−3.3−(−6)−(−334)+4+3.3
(3)−81÷(−214)×49÷(−16)
(4)(−24)×(138+213−0.75)
23.计算:1﹣2+3﹣4+5﹣6+…+2007﹣2008+2009﹣2010+2011.
24.计算:
(1)(18−13+16)×(−24) ;
(2)|−2|×(−1)2013−3÷12×2 ;
(3)−12−(1−0.5)×13×[2−(−3)]2 ;
(4)7×(−36)×(−87)×16 .
25.计算与化简:
(1)4﹣|﹣6|﹣3× (−13) ;
(2)﹣32+(﹣1)2001÷ 16 +(﹣5)2;
(3)2x2y﹣2(3xy﹣x2y)﹣xy;
(4)6a2b﹣[2ab2﹣3(a2b﹣2ab2)].
26.计算:
(1)a3•a2•a
(2)(x3)2+(﹣x2)3﹣x•x5 .
27.计算:
(1)5﹣(﹣2)
(2)16 +(﹣ 13 )
(3)﹣3 ÷3×13
(4)34×(-43)-2÷65 .
28.“*”是规定的一种运算法则: a∗b=a2−b2 ,求 5∗[(−1)∗2] 的值。
29.计算:
(1)(-5)+(+7)-(-3)-(+20)
(2)25÷ 56 ×( −25 )+(-2)×(-1)2019
30.计算下列各题:
(1)(-12)-5+(-17)-(-13)
(2)( −16+58−712) (-24)
(3) −42−−12019÷5×15+−17+21
31.先化简,再求值: −2ab+3a2b−2(a2b−ab) ,其中 a=−1,b=−2
32.计算:
(1)5 14 ﹣(﹣2 23 )+(﹣3 14 )﹣(+4 23 )
(2)(﹣ 34 ﹣ 58 + 912 )×(﹣24)
(3)(﹣3)÷ 34 × 43 ×(﹣15)
(4)﹣14+|(﹣2)3﹣10|﹣(﹣3)÷(﹣1)2017 .
33.计算:① −22+30−−12−1 ②a2·a4+(a2)3
34.若 |x+2| 与 |1−2y| 互为相反数,求 x+y 的值.
35.计算:
(1)25 ﹣|﹣1 12 |﹣(+2 14 )﹣(﹣2.75)
(2)﹣14﹣[1﹣(1﹣0.5× 13 )]×6.
36.解方程: 12y=−12−2y .
37.计算
(1)(3mn+1)(3mn﹣1)﹣8m2n2
(2)(x+2)2﹣(x+1)(x﹣1)
(3)[(x+y)2﹣(x﹣y)2]÷2xy.
38.解下列方程
(1)4x = 20
(2)6x + 6=18
(3)5x ̶ 6 = 24
(4)3x - 9 = 3
39.若|a|=7,|b|=3,且ab>0,求a+b的值.
40.解方程: 7x−3=5x+9
41.计算:
(1)16÷(﹣2)3﹣(﹣ 18 )×(﹣4)
(2)﹣12﹣( 12 ﹣ 23 )÷ 13 ×[﹣2+(﹣3)2].
42.计算:
(1)(−12ab)(23ab2−2ab+43b)
(2)(2x+y)(2x-y)+(x+y)2-2(2x2-xy)
43.解方程:2﹣ 2x+13 = 1+x2 .
44.解方程
(1)3(x−2)=2x−5
(2)x−33=x−3x−16
45.解下列方程:
(1)x−12 = 4x3 +1
(2)0.1x−0.20.02 - x+10.5 =3.
46.先化简再求值:14(-8x2-16y)-13(3x2-9y) ,其中x=12,y=14 .
47.计算:
(1)12−(−18)+(−7)−15
(2)16+(-25)+ 24 +(+25)
48.先化简再求值:
已知多项式A=3a2﹣6ab+b2 , B=﹣2a2+3ab﹣5b2 , 当a=1,b=﹣1时,试求A+2B的值.
49.计算下列各题:
(1)(3.14-π)0+(-1)2019+3-2
(2)(m+1)2-m(m+3)-3
50.
(1)先化简,再求值:x2+2x﹣3(x2﹣ 23 x),其中x=﹣ 12 .
(2)计算: 12 xy﹣2(xy﹣ 13 xy2)+( 32 xy+ 13 xy2),其中x、y满足|x﹣6|+(y+2)2=0.
51.计算:
(1)(+3)−(−5)
(2)(-1)2016+(-2)×(-3)+(-2)3
52.计算
(1)(14−13−1)×(−12)
(2)−22×14+(−3)3×(−827)
53.当x取何值时,代数式3x﹣5与﹣4x+6的值互为相反数.
54.计算
(1)13+7﹣(﹣20)﹣(﹣40)﹣6
(2)0.5+(﹣ 14 )﹣2.75+(﹣ 12 )
(3)(﹣12)﹣5+(﹣14)﹣(﹣39)
(4)25 ﹣|﹣1 12 |﹣(+2 14 )﹣(﹣2.75)
(5)(−423)−(0.5−312)
(6)0.47﹣4 56 ﹣(﹣1.53)﹣1 16 .
55.计算:
(1)-5-(-4)+7-8
(2)312÷(−35)×15
(3)−14−(−3)2×|−49|
(4)(−5)×(−325)+(−7)×325−12×(−325)
56.计算:
(1)2x5⋅(−2x)3−(−x2)3⋅(−7x)2
(2)−12016+(−2)−2−(3.14−π)0−(23)−1
(3)(a−2b)2(a+2b)2
(4)(m−n)(4m−n)+3m(4m−n)
57.先化简,再求值: ,其中a=3,b=1.
58.计算:-32×(5-3)-(-2)2÷l-4l
59.计算:
(1)0÷(-8)×108;
(2)6÷ 23 × 32 ;
(3)-2.5÷ 58 × (−14) ;
(4)(−35) × (−312) ÷ (−114) ÷3.
60.计算:
(1)(a⋅am+1)2−(a2)m+3÷a2
(2)(−13)−2+0.22016×(−5)2015−(−12)0
(3)求代数式 (2a+b)2−(3a−b)(3a+b)+5a(a−b) 的值,其中 a=2 , b=−12 .
61.解方程: (3x−2)+2(x−1)=1
62.已知|a|=4,b2=9,且ab>0,求a-b的值.
63.先化简,再求值:3(2a2+ab)-2(3a2+ab),其中a=-2,b=3。
64.计算下列各题:
(1)(+5)−3−(−6) ;
(2)(2−32+16)×(−32)−(13)2÷518
65.解下列方程:
(1)4x-3(12-x)=6x-2(8-x)
(2)2x−13 - 2x−34 =1
66.计算:
(1)12+(-7)-(-15)
(2)4+(-2)3×5-(-0.28)÷4.
67.先化简,再求值: 5(3a2b−ab2)−4(−ab2+3a2b) ,其中 a=12 , b=−13 .
68.4ab∙(-3a2b2)+(2ab)3
69.解方程
(1)2x=9−x ;
(2)2x+13−5x−16=1 .
70.先化简,再求值:2(2x-3y-1)- 13 (9x+6y-6),其中x=2,y=-0.5.
71.计算:
(1)-14- 16 ×[2-(-3)2]÷(-7);
(2)(1 12 - 58 + 712 )÷(- 124 )-8×(- 12 )3 .
72.计算: (x−y−3)(x+y−3) .
73.解方程:
(1)3x-2=1-2(x+1);
(2)x+45+1=x−x−53 .
74. 计算:
(1)(π−1)0−(−12)−1−1.252017×(45)2018
(2)[(2x﹣y)2﹣(2x+y)(2x﹣y)+4xy]÷2y.
75. 计算
(1)36﹣27×( 73 ﹣ 119 + 227 )
(2)−72+2×(−3)2−(−6)÷(−13)2
76.计算:
(1)-1.5+1.4- (-3.6)-1.4;
(2)−73×47÷(−83) ;
(3)|-2|÷( −12 )+(-5)×(-2);
(4)(23−12+56)×(−24) .
77.计算:-14-(-6)+3×(- 13 )
78.计算25−−112−+214−−2.75
79.计算:
(1)(3x2)2•(﹣4y3)÷(6xy)2;
(2)[(2x﹣y)(2x+y)+y(y﹣6x)]÷2x.
80.用简便方法计算下列各题
(1)(45)2015×(−1.25)2016
(2)(318)12×(825)11×(−2)3 .
81.计算:
(1)(−214)−(+58)+(−14)−(−18)
(2)9−(−4)2÷(−2)
82.化简求值:已知:(x﹣3)2 +|y+13| =0,求3x2y﹣[2xy2﹣2(xy﹣ 32x2y )+3xy]+5xy2的值.
83.计算下列各式:
(1)(﹣1.25)+(+5.25)
(2)(﹣7)+(﹣2)
84.先化简,再求值: [(2a+3b)(2a−3b)−(2a−b)2]÷(−4b) ,其中 a=52 , b=−1.
85.计算:
① (+26)+(−18)+5−16
② −15−[−1−(4−20)]
③ 18×(−23)+13×23−4×23
④ 8×(−45)÷|−16|
⑤ (47−19+221)×(−63)
⑥ (−34)×38÷(−916)×(−18)
86.解方程:
(1)2−x=3x+8 ;
(2)x−3x−14=x6 .
87.①先化简,再求值:(4x+3)(x-2)-2(x-1)(2x-3),x=-2;
②若(x2+px+q)(x2-3x+2)的结果中不含x3和x2项,求p和q的值.
88.解方程:
(1)34x+1=7
(2)32[2(x+13)+23]=5x
89.解方程: 3y+14=2−2y−13 .
90.计算下列各题
(1)319×(−9)+681×(−9) ;
(2)−(213−13−16)×78 ;
(3)−32−|(−5)3|×(−25)2−18÷|−(−3)2|
(4)4−22×(−13)+(−3)3÷214×(−23)2 .
91.解方程:
(1)x﹣4=2﹣5x
(2)5(x+8)=6(2x﹣7)+5
(3)x−74 ﹣ 2x−123 =1
(4)0.5−0.2x0.2 =0.1+ x0.5 .
92.解方程:
(1)5-2x=9-4x
(2)2x−13 =1- 5x+76
93.解方程:
(1)4x=5x﹣5
(2)4x+3(2x﹣3)=12﹣(x﹣4)
(3)x+24−1=2x−36 .
(4)0.2x−0.10.3−10x+16=0.02x+0.010.04−214
94.已知m是8的相反数,n比m的相反数小2,求n比m大多少?
95.若|a|=21,|b|=27,且|a+b|=-(a+b),求a-b的值.
96. 计算:
(1)5 14 -(-2 23 )+(-3 14 )-(+4 23 );
(2)(- 34−58+912 )×(-24);
(3)(-3)÷ 34 × 43 ×(-15);
(4)-14+|(-2)3-10|-(-3)÷(-1)2017 .
97.计算:
(1)−14+12÷(−13)×(−2)3 ;
(2)(−34+56−78)×(−24) .
98.已知1- 12 = 12 , 12 - 13 = 16 , 13 - 14 = 112 , 14 - 15 = 120 ………根据这些等式求值。请你仔细观察,并找出其奥妙,再计算: 11×2+12×3+13×4+⋯+149×50
99.计算:
(1)﹣3+8﹣7﹣15
(2)﹣20+(﹣14)﹣(﹣18)﹣13.
100.
(1)( 34 ﹣ 16 ﹣ 38 )×(﹣24);
(2)﹣22+[12﹣(﹣3)×2]÷(﹣3)
(3)(﹣ 56 )÷|﹣1 23 |+(﹣2)3×(﹣1.5)
答案解析部分
1.答案解:
(a+2b)(2a−b)−(a+2b)2−(a−2b)2=2a2−ab+4ab−2b2−a2−4ab−4b2−a2+4ab−4b2= 当a=- 13 ,b=-3时,原式=-87
2.答案:
(1)解: 1534×1614 .
=(16- 14 )×(16+ 14 ).
=162-( 14 )2.
=256- 116 .
=255 1516.
(2)解: 2a3b2⋅(−3bc2)3÷(−ca2)
= 2a3b2⋅(−27b3c6)÷(−ca2)
=-54a3b5c6÷(−ca2).
=54ab5c5
(3)解:原式 =[(9x2−4y2)−(5x2+8xy−4y2)]÷4x .
=(4x2−8xy)÷4x .
=x−2y.
当x= 12 ,y=2时,
原式= −72.
3.答案:
(1)解:-(-2 13 )=2 13
(2)解:-(+ 0.25)=-0.25
(3)解:-(-a)=a
(4)解:-[-(-2.8)]=-2.8
(5)解:-[-(+1)]=-(-1)=1
(6)解:-[+(-5)]=-(-5)=5
4.答案解:
(-14)-(+15)
=-14-15
=-(14+15) (符号后面添括号,括号里面的数要变号)
=-29
5.答案:
(1)解:原式 =49−58 =−9
(2)解:原式 =19+76−22+52
=147−22
=125
(3)解:原式 =(3.2+1.8)−(1.6+0.4)
=5−2
=3
(4)解:原式 =−7−5+2
=−12+2
=−10
6.答案解:
3x+6=31﹣2x
两边同时加上(2x﹣6),得:3x+6+2x﹣6=31﹣2x+2x﹣6
即:5x=25
两边同时除以5,得:x=5
7.答案解:
原式=-3×56×95×14
=-98
8.答案:
(1)解: −3+8−7
=−3−7+8
=−10+8
=−2 ;
(2)解: 23−6×(−3)+2×(−4)
=8+18−8
=18 ;
(3)解: (−24)×(13−18−16)
=13×(−24)−18×(−24)−16×(−24)
=−8+3+4
=−1 ;
(4)解: (−37)×0.125×(−213)×(−8)
=(−37)×(−73)×(−8)×0.125
=−1 .
9.答案解:
2-4x=x-8,
-4x-x=-8-2,
-5x=-10,
x=2
10.答案:
(1)解:原式=﹣16 34 +10 14 ﹣1 12
=﹣8
(2)解:原式=﹣ 34 × 32 × 49
=﹣ 12
(3)解:原式=4×6﹣(﹣8)÷4
=24+2
=26
(4)解:原式=4a2b﹣5ab2﹣3a2b+4ab2
=a2b﹣5ab2
11.答案解:
原式= 12 x﹣2x+ 23 y2+ 32 x+ 13 y2=y2 ,
∵|x﹣6|+(y+2)2=0,
∴x=6,y=﹣2,
则原式=4
12.答案解:
4a2+2(3ab﹣2a2)﹣(7ab﹣1)=4a2+6ab﹣4a2﹣7ab+1=﹣ab+1.
13.答案解:
原式=﹣8×4﹣(﹣5)×2=﹣32+10=﹣22
14.答案解:
(1)原式=8+2﹣3﹣1=10﹣4=6;
(2)原式=﹣3﹣6=﹣9;
(3)原式=﹣16+18﹣2=﹣18+18=0;
(4)原式=﹣27÷(﹣9)﹣[2+(﹣8)]=3﹣(﹣6)=3+6=9.
15.答案:
(1)解:原式 =−6+20−16=−2
(2)解:原式 =−1+5+3=7
16.答案:
(1)解:解去括号得:4x+2=10x+7
移项合并得:-6x=5
解得:x= -56
(2)解:去括号得:3-2x-2=2x-6
移项合并得:-4x=-7
解得:x= 74
17.答案:
(1)解: 5x=10
x=2
(2)解: 3(x−23)+2=1
3x=1
x=13
18.答案解:
原式=2x2-12+3x-4x+4x2-2
=6x2−x−52
19.答案:
(1)原式= 1−16+(−4×14)2020
=-14;
(2)原式= 4a2−25−4a2+8a
= 8a−25 ;
(3)原式=20192-(2019-1)×(2019+1)
= 20192−20192+1
=1
20.答案解:
4a2+3b2+2ab﹣4a2﹣6b2=4a2﹣4a2+3b2﹣6b2+2ab=﹣3b2+2ab.
21.答案:
(1)解:原式=-5.5-3.2+2.5-4.8,
=-(3.2+4.8)-(5.5-2.5),
=-8-3,
=-11
(2)解:原式=-40-28+19-24,
=-73.
(3)解:原式= (23−112−115)×(−60)
= 23 × (-60)- 112 ×(−60) - 115 × (-60),
=-40+5+4,
=-31
(4)解:原式=-1- 12 × 13 × (-7),
=-1+ 76
= 16
22.答案:
(1)解: (−4)−(+13)+(−5)−(−9)+7
=(−4−13−5)+(9+7)
=−22+16
=−6
(2)解: 614−3.3−(−6)−(−334)+4+3.3
=614−3.3+6+334+4+3.3
=(614+334)+(−3.3+3.3)+(6+4)
=10+0+10
=20
(3)解: −81÷(−214)×49÷(−16)
=−81×(−49)×49×(−116)
=36×49×(−116)
=16×(−116)
=−1
(4)解: (−24)×(138+213−0.75)
=(−24)×118+(−24)×73−(−24)×34
=−33+(−56)−(−18)
=−71
23.答案解:
1﹣2+3﹣4+5﹣6+…+2007﹣2008+2009﹣2010+2011=1+(﹣2+3)+(﹣4+5)+(﹣6+7)+…+(﹣2006+2007)+(﹣2008+2009)+(﹣2010+2011)=1+=1+1005=1006
24.答案:
(1)解:原式 =18×(−24)−13×(−24)+16×(−24)
=−3+8−4
=1
(2)解:原式 =2×(−1)−3÷12×2
=−2−6×2
=−2−12
=−14
(3)解:原式 =−12−12×13×52
=−1−12×13×25
=−1−256
=−316
(4)解:原式 =7×(−87)×(−36)×16
=[7×(−87)]×[(−36)×16]
=(−8)×(−6)
=48 .
25.答案:
(1)解:原式=4﹣6+1
=﹣1;
(2)解:原式=﹣9﹣1×6+25
=﹣9﹣6+25
=10;
(3)解:原式=2x2y﹣6xy+2x2y﹣xy
=4x2y﹣7xy;
(4)解:原式=6a2b﹣2ab2+3a2b﹣6ab2
=9a2b﹣8ab2.
26.答案:
(1)解:a3•a2•a=a3+2+1=a6
(2)解:(x3)2+(﹣x2)3﹣x•x5
=x6+(﹣x6)﹣x6=﹣x6 .
27.答案:
(1)解:原式=5+2=7
(2)解:原式= 16 ﹣ 13 =﹣ 16
(3)解:原式=﹣3× 13 × 13 =﹣ 13
(4)解:原式=﹣1﹣ 53 =﹣ 83
28.答案解:
解:∵a*b=a2-b2 ,
∴(-1)*2=(-1)2-22=1-4=-3,
∴5*(-3)=52-(-3)2=25-9=16.
29.答案:
(1)解:(-5)+(+7)-(-3)-(+20)
=-5+7+3- 20
=-25+10
=-15
(2)解:25÷ 56 ×( −25 )+(-2)×(-1)2019
=25× 65 ×( −25 )+(-2)×(-1)
=-12+2
=-10
30.答案:
(1)解:原式= −12+−5+−17+13= -34+13
= -21
(2)解:原式= −16×−24+58×−24−712×−24= 4+(-15)-(-14)
= 4+(-15)+14
=
(3)解:原式= −16−−1×15×15+4= −16−−125+4
= −12+125
= −112425.
31.答案解:
原式=-2ab+3a2b-2 a2b+2ab=-2ab+2ab+3 a2b-2 a2b= a2b;当 a=−1,b=−2 时,原式=(-1)2×(-2)= -2
32.答案:
(1)解:原式=5 14 +2 23 ﹣3 14 ﹣4 24
=5 14 ﹣3 14 +2 23 ﹣4 23
=2﹣2
=0
(2)解:原式= 34 ×24+ 58 ×24﹣ 912 ×24
=18+15﹣18
=15
(3)解:原式=(﹣3)× 43 × 43 ×(﹣15)
=4×4×5
=80
(4)解:原式=﹣1+|﹣8﹣10|﹣(﹣3)÷(﹣1)
=﹣1+18﹣3
=14
33.答案解:
(1)原式=-4+1+2=-1;
(2)原式=a6+a6=2a6.
34.答案解:
因为|x+2|与|1-2y|互为相反数,
所以|x+2|+|1-2y|=0,
所以|x+2|=0,|1-2y|=0,即x+2=0,1-2y=0,
所以x=-2,y= 12 .
所以x+y=-2+ 12 =- 32
35.答案:
(1)解:原式=0.4﹣1.5﹣2.25+2.75=0.4﹣3.75+2.75=0.4﹣1=﹣0.6
(2)解:原式=﹣1﹣(1﹣1+ 16 )×6=﹣1﹣1=﹣2
36.答案解:
移项: 12y+2y=−12 ,
合并同类项: 52y=−12 ,
化系数为1: y=−15
37.答案:
(1)解:原式=9m2n2﹣1﹣8m2n2=m2n2﹣1
(2)解:原式=x2+4x+4﹣x2+1=4x+5
(3)解:原式=(x2+2xy+y2﹣x2+2xy﹣y2)÷2xy=4xy÷2xy=2
38.答案:
(1)解:系数化为1得 x=5
(2)解:移项得 6x=18−6 ,
系数化为1得 x=2
(3)解:移项得 5x=24+6 ,
系数化为1得 x=6
(4)解:移项得 3x=3+9 ,
系数化为1得 x=4
39.答案解:
|a|=7,|b|=3,且ab>0,
a=7,b=3,或a=﹣7,b=﹣3,
a+b=7+3=10或a+b=﹣10
40.答案解:
7x−5x=9+3,
2x=12
x=6
41.答案:
(1)解:16÷(﹣2)3﹣(﹣ 18 )×(﹣4)
=16÷(﹣8)﹣ 12
=﹣2﹣ 12
=﹣2 12
(2)解:﹣12﹣( 12 ﹣ 23 )÷ 13 ×[﹣2+(﹣3)2]
=﹣1+ 16 ÷ 13 ×[﹣2+9]
=﹣1+ 12 ×7
= 52
42.答案:
(1)解: (−12ab)(23ab2−2ab+43b)
= −13a2b3+a2b2−23ab2
(2)解:(2x+y)(2x-y)+(x+y)2-2(2x2-xy)
=4x2-y2+x2+2xy+y2-4x2+2xy
=
x2+4xy.
43.答案解:
去分母得,12﹣2(2x+1)=3(1+x),
去括号得,12﹣4x﹣2=3+3x,
移项得,﹣4x﹣3x=3﹣12+2,
合并同类项得,﹣7x=﹣7,
系数化为1得,x=1
44.答案:
(1)3(x-2)=2x-5
解:3x-6=2x-5
x=1
(2)x−33=x−3x−16
解:2(x-3)=6x-(3x-1)
2x-6=6x-3x+1
x=-7
45.答案:
(1)解: 3(x−1)=8x+6,
3x−3=8x+6,
3x−8x=6+3,
−5x=9,
x=−95.
(2)解: 5x−10−2(x+1)=3,
5x−10−2x−2=3,
3x=15,
x=5.
46.答案解:
14(-8x2-16y)-13(3x2-9y)
=-2x2-4y-x2+3y=-3x2-y
当x=12,y=14时,-3x2-y=-3×(12)2-14=-1.
47.答案:
(1)解:原式=12+18+(-7)+(-15)
=(12+18)+[(-7)+(-15)]
=30+(-22)
=30-22
=8
(2)解:原式=16+(-25)+24+25
=(16+24)+(25-25)
=40+0
=40
48.答案解:
A+2B=3a2﹣6ab+b2+2(﹣2a2+3ab﹣5b2)=3a2﹣6ab+b2﹣4a2+6ab﹣10b2=﹣a2﹣9b2 ,
当a=1,b=﹣1 时原式=﹣12﹣9×(﹣1)2=﹣10
49.答案:
(1)解: 原式=1-1+19
=19;
(2)解: 原式=m2+2m+1-m2-3m-3
=-m-2
50.答案:
(1)解:原式=x2+2x﹣3x2+2x=﹣2x2+4x,
当x=﹣ 12 时,原式=﹣ 12 ﹣2=﹣2 12
(2)解:原式= 12 xy﹣2xy+ 23 xy2+ 32 xy+ 13 xy2=xy2 ,
由|x﹣6|+(y+2)2=0,得到x=6,y=﹣2,
则原式=24
51.答案:
(1)解:原式 =3+5=8
(2)解:原式 =1+6−8=−1
52.答案:
(1)解:原式= 14×(−12)−13×(−12)−1×(−12)
= −3+4+12
=13
(2)解:原式= −4×14+(−27)×(−827)
= −1+8
=7
53.答案解:
根据题意,得:3x﹣5+(﹣4x+6)=0,
去括号,得:3x﹣5﹣4x+6=0,
移项,得:3x﹣4x=5﹣6,
合并同类项,得:﹣x=﹣1,
系数化为1,得:x=1.
54.答案:
(1)解:原式=13+7+20+40﹣6=74
(2)解:原式=0.5﹣ 12 ﹣ 14 ﹣2.75=﹣3
(3)解:原式=﹣12﹣5﹣14+39=8
(4)解:原式= 25 ﹣1 12 ﹣2 14 +2.75=﹣ 35
(5)解:原式=﹣4 23 +3 12 ﹣0.5=﹣1 23
(6)解:原式=0.47+1.53﹣4 56 ﹣1 16 =2﹣6=﹣4
55.答案:
(1)解:-5-(-4)+7-8, =-5+4+7-8, =-2
(2)解: 312÷(−35)×15 , = −72×135×15 , = −150
(3)解: −14−(−3)2×|−49| , = −1−9×49 , =-1-4, =-5
(4)解: (−5)×(−325)+(−7)×325−12×(−325) , = 5×325−7×325+12×325 , = 325×(5−7+12) =34
56.答案:
(1)2x5⋅(−2x)3−(−x2)3⋅(−7x)2
= 2x5⋅(−8x3)+x6⋅49x2
= −16x8+49x8
= 33x8
(2)−12016+(−2)−2−(3.14−π)0−(23)−1
= −1+14−1−32
= −134
(3)(a−2b)2(a+2b)2
= [(a−2b)(a+2b)]2
= (a2−4b2)2
= a4−8a2b2+16b4
(4)(m−n)(4m−n)+3m(4m−n)
= (4m−n)(m−n+3m)
= (4m−n)(4m−n)
= 16m2−8mn+n2 .
57.答案解:
原式=-2ab+3a-4a+2b+2ab
=-a+2b
当a=3,b=1时,原式=-3+2×1=-1
58.答案解:
原式=-9×2-4÷4
=-18-1
=-19
59.答案:
(1)解:原式=0
(2)解:原式=6× 32 × 32 = 272
(3)解:原式=- 52 × 85 × (−14) =1
(4)解:原式=- 35 × 72 × 45 × 13 =- 1425
60.答案:
(1)解:原式= a2⋅a2m+2−a2m+6÷a2=a2m+4−a2m+4 =0.
(2)解:原式= 9+(−5×0.2)2015×0.2−1 =9−0.2−1=7.8.
(3)解:(2a+b) ²−(3a−b)(3a+b)+5a(a−b)=4a²+4ab+b²−9a²+b²+5a²−5ab=−ab+2b²,
当a=2、b=− 12 时,
原式= 32.
61.答案解:
3x−2+2x−2=1 ,
3x+2x=1+2+2 ,
x=1
62.答案解:
∵|a|=4,b2=9,
∴a=±4,b=±3,
又∵ab>0,
∴a、b同号,
①当a=4,b=3时,
∴a-b=4-3=1;
②当a=-4,b=-3时,
∴a-b=-4-(-3)=-1;
综上所述:a-b的值为1或-1.
63.答案:
解:3(2a2+ab)-2(3a2+ab)=6a2+3ab-6a2-2ab=ab,
当a=-2,b=3时,原式=-2×3=-6
64.答案:
(1)解:原式=5-3+6=8;
(2)解:原式= 2×(−32)−32×(−32)+16×(−32)−19×185
= −3+94−14−25
= −75
65.答案:
(1)解:4x-3(12-x)=6x-2(8-x)
4x-36+3x=6x-16+2x
4x+3x-6x-2x=-16+36
-x=20
x=-20
(2)解:4(2x-1)-3(2x-3)=12
8x-4-(6x-9)=12
8x-6x=12+4-9
2x=7
x= 72
66.答案:
(1)解:原式 =12−7+15=27−7=20;
(2)解:原式 =4−8×5+0.7=4−40+0.07=−35.93.
67.答案解:
原式化简= 3a2b−ab2
代入求值= −1136
68.答案解:
原式 =−12a3b3+8a3b3
=−4a3b3 .
69.答案:
(1)解:移项,可得:2x+x=9,
合并同类项,可得:3x=9,
系数化为1,可得:x=3;
(2)解:去分母,可得:2(2x+1)−(5x−1)=6,
去括号,可得:4x+2−5x+1=6,
移项,合并同类项,可得:x=−3.
70.答案解:
原式=4x-6y-2-3x-2y+2
=x-8y
把x=2,y=-0.5代入x-8y, 得
2-8×(-0.5)=2+4=6
71.答案:
(1)解:原式= −1−16×[2−9]÷(−7) = −1−16×(−7)×(−17) = −1−16 = −76
(2)解:原式= (32−58+712)×(−24)−8×(−18) =-36+15-14+1=-34
72.答案解:
原式= (x−3−y)(x−3+y)
= (x−3)2−y2
= x2−6x+9−y2
73.答案:
(1)解:3x-2=1-2(x+1),
3x-2=1-2x-2,
5x=1,
x=15 ;
(2)解: x+45+1=x−x−53 ,
3(x+4)+15=15x-5(x-5),
3x+12+15=15x-5x+25,
7x=2,
x= 27 .
74.答案:
(1)解:原式=1+2﹣ 45 ×( 54 × 45 )2017=1+2﹣ 45 =2 15
(2)解:原式=(4x2﹣4xy+y2﹣4x2+y2+4xy)÷2y=(2y2)÷2y=y
75.答案:
(1)解:原式=36-63+33-2=4
(2)解:原式=49+2×9-(-6)×9
=-49+18+54
=-31+54
=23
76.答案:
(1)解:原式 =−1.5+1.4+3.6−1.4=2.1 ;
(2)解:原式 =−43×(−38)=12 ;
(3)解:原式 =2×(−2)+10=−4+10=6 ;
(4)解:原式 =(46−36+56)×(−24)=1×(−24)=−24 .
77.答案解:
原式=-1+6+(-1)
=4
78.答案解:
25−−112−+214−−2.75 ,
=25﹣112﹣214+2.75,
=﹣1.1﹣2.25+2.75,
=﹣3.35+2.75,
=﹣0.6.
79.答案:
(1)解:原式=(9x4)•(﹣4y3)÷(36x2y2)
=-36 x4y3÷(36x2y2)
=﹣x2y;
(2)解:原式=(4x2﹣y2+y2﹣6xy)÷2x
=(4x2﹣6xy)÷2x
=2x﹣3y.
80.答案:
(1)解: (45)2015×(−1.25)2016
= (45)2015×(−54)2016×(−54)
=[ 45×(−54) ]2015×(﹣ 54 )
=﹣1×(﹣ 54 )
= 54
(2)解:原式= 258 ×( 258 )11×( 825 )11×(﹣8)=﹣25× (258×825)11
=﹣25.
81.答案:
(1)解: (−214)−(+58)+(−14)−(−18)= (−94)−58+(−14)+18= −(94+14)+(−58+18)=−52−12=−3 ;
(2)解: 9−(−4)2÷(−2)=3−16÷(−2)=3+8=11
82.答案解:
∵(x﹣3)2 +|y+13| =0,
∴x﹣3=0,|y +13 |=0,
解得x=3,y=﹣ 13 ;
3x2y﹣[2xy2﹣2(xy﹣ 32x2y )+3xy]+5xy2
=3x2y﹣2xy2+2xy﹣2× 32x2y ﹣3xy+5xy2
=3x2y﹣2xy2+2xy﹣3x2y﹣3xy+5xy2
=3xy2﹣xy
=3×3× (−13)2 ﹣3×(﹣ 13 )
=1+1
=2.
∴3x2y﹣[2xy2﹣2(xy﹣ 32x2y )+3xy]+5xy2的值是2.
83.答案:
解;(1)(﹣1.25)+(+5.25)
=5.25﹣1.25
=4;
(2)(﹣7)+(﹣2)
=﹣(7+2)
=﹣7
84.答案解:
原式=(4a2−6ab+6ab−9b2−4a2+4ab−b2)÷(-4b).=(4ab−10b2)÷(-4b).=4ab÷(-4b)−10b2÷(-4b).= −a+52b ,当a= 52 ,b=-1时,原式= −52 − 52 =−5.
85.答案解:
① (+26)+(−18)+5−16
=26-18+5-16
=-3
② −15−[−1−(4−20)]
=-15-15
=-30
③ 18×(−23)+13×23−4×23
=-12+ 263 - 83
=-12+6
=-6
④ 8×(−45)÷|−16|
=- 325×116
= -25
⑤ (47−19+221)×(−63)
=-36+7-6
=-35
⑥ (−34)×38÷(−916)×(−18)
= −932×(−169)×(−18)
= -116
86.答案:
(1)解: 2−x=3x+8
移项,得: -x−3x=8-2
合并同类项,得: −4x=6
系数化为1,得: x=−32
(2)解: x−3x−14=x6
去分母,得: 12x-3(3x−1)=2x
去括号,得: 12x-9x+3=2x
移项,得: 12x-9x-2x=-3
合并同类项,得: x=-3
87.答案解:
①(4x+3)(x-2)-2(x-1)(2x-3),
= 4x2−8x+3x−6−2(2x2−3x−2x+3) ,
= 4x2−5x−6−4x2+10x−6 ,
= 5x−12
∵x=-2,
∴原式=-10-12=-22;
②(x2+px+q)(x2-3x+2),
= x4−3x3+2x2+px3−3px2+2px+qx2−3qx+2q ,
= x4+(p−3)x3+(2−3p+q)x2+(2p−q)x+2q ,
∵结果中不含x3和x2项,
∴ p−3=0 , 2−3p+q=0 ,
∴p=3,
∴q=7.
88.答案:
(1)解: 34x+1=7
去分母得, 3x+4=28
移项,合并同类项得, 3x=24
系数化为1,得: x=8
(2)解: 32[2(x+13)+23]=5x
去括号得: 3(x+13)+1=5x
3x+1+1=5x
移项,合并同类项得, 2x=2
系数化为1,得: x=1
89.答案解:
去分母,得3(y+1)=24﹣4(2y﹣1),
去括号,得9y+3=24﹣8y+4,
移项,得 9y+8y=24+4﹣3,
合并同类项,得17y=25,
系数化为1,得y= 2517
90.答案:
(1)解:原式 =(319+681)×(−9)=1000×(−9)=−9000.
(2)解:原式 =−(213×78−13×78−16×78)=−(12−26−13)=−(−27)=27.
(3)解:原式 =−9−125×425−18×19=−9−20−2=−31.
(4)解:原式 =4−4×(−13)+(−27)×49×49=4+43−163=163−163=0.
91.答案:
(1)解:移项,得:x+5x=2+4,
合并同类项,得:6x=6,
解得x=1.
(2)解:去括号,得:5x+40=12x﹣42+5,
移项,合并同类项,可得:7x=77,
解得x=11.
(3)解:去分母,可得:3(x﹣7)﹣4(2x﹣12)=12,
去括号,可得:﹣5x+27=12,
移项,合并同类项,可得:5x=15,
解得x=3.
(4)解:去分母,可得:5(0.5﹣0.2x)=0.1+2x,
去括号,可得:﹣x+2.5=0.1+2x,
移项,合并同类项,可得:3x=2.4,
解得x=0.8.
92.答案:
(1)5-2x=9-4x
-2x+4x=9-5
2x=4
x=2;
(2)2x−13 =1- 5x+76
2(2x-1)=6-(5x+7)
4x-2=6-5x-7
4x+5x=6-7+2
9x=1
x= 19
93.答案:
(1)解:4x=5x﹣5
4x﹣5x=﹣5,
则﹣x=﹣5,
解得:x=5
(2)解:去括号得,4x+6x﹣9=12﹣x+4,
移项得,4x+6x+x=12+4+9,
合并同类项得,11x=25,
系数化为1得,x= 2511
(3)解: x+24 ﹣1= 2x−36
去分母得:3(x+2)﹣12=2(2x﹣3),
去括号得:3x+6﹣12=4x﹣6,
移项得:3x﹣4x=﹣6﹣6+12,
合并同类项得:-x=0
系数化为1得:x=0
(4)解:去分母得,4(2x﹣1)﹣2(10x+1)=3(2x+1)﹣27,
去括号得,8x﹣4﹣20x﹣2=6x+3﹣27,
移项得,8x﹣20x﹣6x=3﹣27+4+2,
合并同类项得,﹣18x=﹣18,
系数化为1得,x=1
94.答案解:
∵m是8的相反数,
∴m=﹣8,
∵n比m的相反数小2,
∴n=﹣(﹣8)﹣2=6,
∴n﹣m=6﹣(﹣8)=14,
故n比m大14
95.答案解:
∵|a|=21,|b|=27,
∴a=±21,b=±27,
又∵|a+b|=-(a+b),
∴a+b<0,
∴a=±21,b=-27,
①当a=21,b=-27时,
∴a-b=21-(-27)=48;
②当a=-21,b=-27时,
∴a-b=-21-(-27)=6;
综上所述:a-b的值为48或6.
96.答案:
(1)解:原式=5 14 +2 23 ﹣3 14 ﹣4 23
=5 14 ﹣3 14 +2 23 ﹣4 23
=2﹣2
=0;
(2)解:原式= 34 ×24+ 58 ×24﹣ 912 ×24
=18+15﹣18
=15;
(3)解:原式=(﹣3)× 43 × 43 ×(﹣15)
=4×4×5
=80
(4)解:原式=﹣1+|﹣8﹣10|﹣(﹣3)÷(﹣1)
=﹣1+18﹣3
=14.
97.答案:
(1)解: −14+12÷(−13)×(−2)3
= −1+12×(−3)×(−8) ,
=-1+12
=11
(2)解: (−34+56−78)×(−24)
= (−34)×(−24)+56×(−24)−(78)×(−24) ,
=18-20+21
=19
98.答案解:
11×2+12×3+13×4+⋯+149×50
= 1-12+12-13+13-14+⋯+149-150
= 1-150
= 4950
99.答案:
(1)解:原式=﹣25+8=﹣17;
(2)解:原式=﹣20﹣14+18﹣13=﹣47+18=﹣29.
100.答案:
(1)解:( 34 ﹣ 16 ﹣ 38 )×(﹣24);
=(﹣18)+4+9,
=﹣5
(2)解:﹣22+[12﹣(﹣3)×2]÷(﹣3),
=﹣4+(12+6)÷(﹣3),
=﹣4+18÷(﹣3),
=﹣4+(﹣6),
=﹣10
(3)解:(﹣ 56 )÷|﹣1 23 |+(﹣2)3×(﹣1.5),
=(﹣ 56 )× 35 +(﹣8)×(﹣1.5),
=﹣ 12 +12,
=11 12
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