Question

please slove question no.
9,12,15

Answer 1

I hope my answer is helpful for you.

Answer 2

(9) 1.
RHS = (x+y) (x²-xy+y²)
=x(x²-xy+y²) +y(x²-xy+y²)
=x³-x²y+xy²+x²y-xy²+y³
=x³+y³=LHS