Question

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

Answer 1

(2ab)(-2ab)+(3ab)(3ab+2)

=-4a*a*b*b+9a*a*b*b+6a*b

=5a*a*b*b+6ab

=ab(5ab+6)

a=3,b=2

那么 ab(5ab+6)=3*2*（5*3*2+6）

=216