(1)-12+15-|-7-8|(2)(-3)×(-9)-(-5)(3)23-17-(-7)+(-16)(4)36×(19-16-118)(5)-13-(1-0.5)×13×[2-(-3)2](6)16÷(-2)3-(-18)×(-4)+(-1)100(7)化简求值5ab2+3a2b-3(a2b-23ab2),-数学
题文
(1)-12+15-|-7-8| (2)(-3)×(-9)-(-5) (3)23-17-(-7)+(-16) (4)36×(
(5)-13-(1-0.5)×
(6)16÷(-2)3-(-
(7)化简求值5ab2+3a2b-3(a2b-
(8)化简求值2(x2y+xy2)-2(x2y-1)-3xy2-2,其中x=-2,y=
|
答案
(1)-12+15-|-7-8| =-12+15-|-15| =-12+15-15 =-12; (2)(-3)×(-9)-(-5) =27+5 =32; (3)23-17-(-7)+(-16) =(23+7)+(-17-16) =30+(-33) =-3; (4)36×(
=36×
=4-6-2 =-4; (5))-13-(1-0.5)×
=-1-
=-1-
=
(6)16÷(-2)3-(-
=16÷(-8)-
=-2-
=-2+(-
=-
(7)5ab2+3a2b-3a2b+2ab2 =5ab2++2ab2+3a2b-3a2b =7ab2, 当a=2,b=-1时, 原式=7×2×(-1)2=14; (8)2x2
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