Question

化简(x²+xy+y²)(x²-xy+y²)=?

Answer 1

(x²+xy+y²)(x²-xy+y²)=[(x²+y²)+xy][(x²+y²)-xy]
=(x²+y²)²-(xy)²
=x^4+2x²y²+y^4-x²y²
=x^4+x²y²+y^4