(1)计算:?32×[?32×(?23)2+(?2)3](2)23×(-5)-(-3)÷3128(3)化简求值:5(3a2b-ab2)-(ab2+
(1)计算:?32×[?32×(?23)2+(?2)3](2)23×(-5)-(-3)÷3128(3)化简求值:5(3a2b-ab2)-(ab2+3a2b),其中a=12...
(1)计算:?32×[?32×(?23)2+(?2)3](2)23×(-5)-(-3)÷3128(3)化简求值:5(3a2b-ab2)-(ab2+3a2b),其中a=12,b=13.
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推荐于2016-06-13
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(1)
?×[?32×(?)2+(?2)3],
=-
×[-9×
+(-8)],
=-
×(-12),
=18;
(2)23×(-5)-(-3)÷
,
=-115+3×
,
=115+128,
=243;
(3)5(3a
2b-ab
2)-(ab
2+3a
2b),
=15a
2b-5ab
2-ab
2-3a
2b,
=12a
2b-6ab
2=6ab(2a-b),
将
a=,b=代入计算得:
6ab(2a-b),
=6×
×
(2×
-
),
=
,
故5(3a
2b-ab
2)-(ab
2+3a
2b)=
.
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