题目内容
计算:(1)(π﹣3)0﹣
+
×(﹣1.5)2009
(2)2(a4)3+(﹣2a3)2(﹣a2)3+a2a10
(3)先化简,再求值:2a(a﹣2b)﹣(a﹣2b)2,其中a=
,b=﹣
.
(2)2(a4)3+(﹣2a3)2(﹣a2)3+a2a10
(3)先化简,再求值:2a(a﹣2b)﹣(a﹣2b)2,其中a=
解:(1)(π﹣3)0﹣
+
×(﹣1.5)2009
=1﹣2+(
)2008×(﹣1.5)2008×(﹣1.5)
=﹣1﹣1.5
=﹣2.5;
(2)2(a4)3+(﹣2a3)2·(﹣a2)3+a2a10
=2a12+4a6(﹣a6)+a12
=2a12﹣4a12+a12
=﹣a12;
(3)∵2a(a﹣2b)﹣(a﹣2b)2
=2a2﹣4ab﹣(a2﹣4ab+4b2)
=2a2﹣4ab﹣a2+4ab﹣4b2
=a2﹣4b2,
把a=
,b=﹣
,分别代入a2﹣4b2,
∴a2﹣4b2=(
)2﹣4(
)2=
﹣4×
=﹣
.
=1﹣2+(
=﹣1﹣1.5
=﹣2.5;
(2)2(a4)3+(﹣2a3)2·(﹣a2)3+a2a10
=2a12+4a6(﹣a6)+a12
=2a12﹣4a12+a12
=﹣a12;
(3)∵2a(a﹣2b)﹣(a﹣2b)2
=2a2﹣4ab﹣(a2﹣4ab+4b2)
=2a2﹣4ab﹣a2+4ab﹣4b2
=a2﹣4b2,
把a=
∴a2﹣4b2=(
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