(1)-12+15-|-7-8|(2)(-3)×(-9)-(-5)(3)23-17-(-7)+(-16)(4)36×(19?16?118)(5)?13?
(1)-12+15-|-7-8|(2)(-3)×(-9)-(-5)(3)23-17-(-7)+(-16)(4)36×(19?16?118)(5)?13?(1?0.5)×1...
(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),其中a=2,b=-1(8)化简求值2(x2y+xy2)-2(x2y-1)-3xy2-2,其中x=-2,y=12.
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2015-01-17
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(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×?36×?36×=4-6-2
=-4;
(5))
?13?(1?0.5)××[2?(?3)2]=-1-
××(2?9)=-1-
××(?7)=
;
(6)
16÷(?2)3?(?)×(?4)+(?1)100=16÷(-8)-
+1
=-2-
+1
=-2+(-
)+1
=-
;
(7)5ab
2+3a
2b-3a
2b+2ab
2
=5ab
2++2ab
2+3a
2b-3a
2b
=7ab
2,
当a=2,b=-1时,
原式=7×2×(-1)
2=14;
(8)2x
2y+2xy
2-2x
2y+2-3xy
2-2
=2xy
2-3xy
2
=-xy
2,
当x=-2,y=
时,
原式=-(-2)×
()2=(-2)×
=-
.
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