北京师范大学出版社出版的 九年级 下册 数学书 第二章 复习题的 1、5、8、10、11、12、16、18、题的答案。 70
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5(1),1 +5/6-9 / 12 = 12/12 +10/12-9 / 12 = 13/12
(2)3×(-9)7×(-9)= -27-63 = -90
(3)(5/4-7/6)×(-8 / 7)=(15/12-14/12)*(-8 / 7)= 1/12 *(-8 / 7)= -2 / 21
?÷6÷(-3)= 54/6/3 = 3(4)(-54)
(5)2×{5 +(-2)3} = 2 *(5-8)= 2 *(-3)= -6
(6) - (2/13-1/3-1/6)×78 = - (12/78-26/78-13/78)* 78 = - (-27/78)* 78 = 27
6。 (1)3b的2 - (2 + b 2分配)-β2 = 3b的2-2-B 2-B 2 = b的2-2
(2)×(2×1) - (为x / 3 3)= 2 x-1-x/3-3 = 8x/3-9
(3)-2点(ab-3a的2)+(5AB-2)=-2AB 6 2 5从头-2 = 3AB 5 2
(4)2a的2 -1 / 2(从头+ a 2)的-8AB = 2a 2上-1/2ab-1/2a 2-8AB = 3/4a 2 -17/2ab
(5) - (β-4)4的(-b-3)=-b的+4-4β-12 =-5b的-8
(6)1/2(×2-y)的1/3板(xy 2)1/6(X 2 + Y 2)= 1/2X 2 -1/2y +1 / 3x-1/3y 2 +1 / 2 +1 / 6Y = 2/3x 2 -1/2y 6倍+1 / 3x-1/6y 2
11溶液,下面的等式:
(1)16X-40 = 9X +16
????16X-9X = 40 +16
??????7X = 56
??????= 56/7 = 8?
(2)4X = 20/3x +16
??4x-20/3x = 16
12/3x-20/3x = 16
?????-8/3x = 16
???????X = 16 * 3 /(-8)
????????= -6
(3)2(3-x)的= -4(5)
????????6-2X-4X-20
???????6 +20 =-4X +2 X
?????????26 =-2X
??????????= -13
(4)3(-2x的-5)2 = 9
???????-6X-15 +2 = 9
?????????????-4X = 9 +15
?????????????= -24 / 4
?????????????X = -6
(5)1/2(4) - (3×4)= -15 / 2
????????????1/2x-2-3x-4 = -15 / 2
????????????????-5/2x-6 = -15 / 2
15/2-6 = 5/2x????????????????
??????????????15/2-12/2 = 5/2x
???????????????????3/2 = 5/2x
????????????????????= 3/5
(6)x-7/4-5x 8/3 = 1
????4X = 1 +7/4-8 / 3
?????4X = 12/12 +21/12-32 / 12
?????4X = 1/12
??????= 1/48
我希望我的回答对您有帮助
(2)3×(-9)7×(-9)= -27-63 = -90
(3)(5/4-7/6)×(-8 / 7)=(15/12-14/12)*(-8 / 7)= 1/12 *(-8 / 7)= -2 / 21
?÷6÷(-3)= 54/6/3 = 3(4)(-54)
(5)2×{5 +(-2)3} = 2 *(5-8)= 2 *(-3)= -6
(6) - (2/13-1/3-1/6)×78 = - (12/78-26/78-13/78)* 78 = - (-27/78)* 78 = 27
6。 (1)3b的2 - (2 + b 2分配)-β2 = 3b的2-2-B 2-B 2 = b的2-2
(2)×(2×1) - (为x / 3 3)= 2 x-1-x/3-3 = 8x/3-9
(3)-2点(ab-3a的2)+(5AB-2)=-2AB 6 2 5从头-2 = 3AB 5 2
(4)2a的2 -1 / 2(从头+ a 2)的-8AB = 2a 2上-1/2ab-1/2a 2-8AB = 3/4a 2 -17/2ab
(5) - (β-4)4的(-b-3)=-b的+4-4β-12 =-5b的-8
(6)1/2(×2-y)的1/3板(xy 2)1/6(X 2 + Y 2)= 1/2X 2 -1/2y +1 / 3x-1/3y 2 +1 / 2 +1 / 6Y = 2/3x 2 -1/2y 6倍+1 / 3x-1/6y 2
11溶液,下面的等式:
(1)16X-40 = 9X +16
????16X-9X = 40 +16
??????7X = 56
??????= 56/7 = 8?
(2)4X = 20/3x +16
??4x-20/3x = 16
12/3x-20/3x = 16
?????-8/3x = 16
???????X = 16 * 3 /(-8)
????????= -6
(3)2(3-x)的= -4(5)
????????6-2X-4X-20
???????6 +20 =-4X +2 X
?????????26 =-2X
??????????= -13
(4)3(-2x的-5)2 = 9
???????-6X-15 +2 = 9
?????????????-4X = 9 +15
?????????????= -24 / 4
?????????????X = -6
(5)1/2(4) - (3×4)= -15 / 2
????????????1/2x-2-3x-4 = -15 / 2
????????????????-5/2x-6 = -15 / 2
15/2-6 = 5/2x????????????????
??????????????15/2-12/2 = 5/2x
???????????????????3/2 = 5/2x
????????????????????= 3/5
(6)x-7/4-5x 8/3 = 1
????4X = 1 +7/4-8 / 3
?????4X = 12/12 +21/12-32 / 12
?????4X = 1/12
??????= 1/48
我希望我的回答对您有帮助
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