Question

若a+b+3的绝对值+（2a-b）=0,计算4a的三次方b-9ab的三次方

Answer 1

|a+b+3|+(2a-b)^2=0,

∴a+b+3=0,2a-b=0,

解得a=-1,b=-2.

∴4a^3b-9ab^3=ab(4a^2-9b^2)=2(4-36)=-64.