Question

已知（a+2)的平方+3b-1的绝对值=0；求3a平方b-[2ab的平方-6（ab-0.5a的平方b）+4ab]-2ab

Answer 1

∵(a+2)^2恒≥0 ,|3b-1|恒≥0

∴a=-2 ,b=1/3

3a^2b - [2ab^2 - 6(ab - 0.5a^2b) + 4ab] - 2ab

=3a^2b - (2ab^2 - 6ab + 3a^2b + 4ab) - 2ab

=3a^2b - 2ab^2 + 6ab - 3a^2b - 4ab - 2ab

=-2ab^2

=(-2)×(-2)×(1/3)^2

=4/9