先化简,再求值 (2ab)(-2ab)+(3ab)(3ab+2),期中a-3,b=2

分类: 作业答案 • 2022-02-05 16:13:50

问题描述：

先化简,再求值 (2ab)(-2ab)+(3ab)(3ab+2),期中a-3,b=2
快

答

=2ab[-2ab+(ab)(3ab+2)]
=2ab*ab[-ab+3ab+2]
=2ab*ab[2ab+2]
=4ab*ab[ab+1]
=4a的平方b的平方[ab+1]
代入a=3,b=2
=4*9*4*[3*2+1]
=144*7
=1008