posted by siyad on .
find the value of x^3+y^3-12xy+64 when x+y= -4
Nothing is more fun that cubic equations, in school, most are trick questions, such as this. In real life, they are challenging.
(x+y)(x^2-xy+y^2) -12xy +64=A
now divide through by -4
A=320 which answers the question.
Better check the ± signs