计算与化简:(1)计算:-32÷94+49÷(-2)2(2)化简:(3m-2n)-(3m-6n+5)(3)化简,并求值:-(3a2-4ab)+[a2-2(2a+2ab)],其中a=-2,b=2009.

题目简介

计算与化简:(1)计算:-32÷94+49÷(-2)2(2)化简:(3m-2n)-(3m-6n+5)(3)化简,并求值:-(3a2-4ab)+[a2-2(2a+2ab)],其中a=-2,b=2009.

题目详情

计算与化简:
(1)计算:-32÷
9
4
+
4
9
÷(-2)2

(2)化简:(3m-2n)-(3m-6n+5)
(3)化简,并求值:-(3a2-4ab)+[a2-2(2a+2ab)],其中a=-2,b=2009.
题型:解答题难度:中档来源:不详

答案

(1)原式=-9×class="stub"4
9
+class="stub"4
9
×class="stub"1
4
=-4+class="stub"1
9
=-3class="stub"8
9

(2)原式=3m-2n-3m+6n-5=4n-5;
(3)原式=-3a2+4ab+a2-4a-4ab=-2a2-4a,
当a=-2,b=2009时,原式=-8+8=0.

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