(x+3y)(x-3y)(x的2次方-9y的2次方)

问题描述:

(x+3y)(x-3y)(x的2次方-9y的2次方)

(x+3y)(x-3y)(x²-9y²)
=(x²-9y²)(x²-9y²)
=(x²-9y²)²

(x+3y)(x-3y)(x²-9y²)
=(x²-9y²)(x²-9y²)
=(x²-9y²)²
=x^4-18x²y²+81y^4