Question

x的2次方-6xy+9y的2次方+x的2次方y-9y的3次方

Answer 1

x^2-6xy+9y^2+x^2y-9y^3

=(x-3y)^2+y(x^2-9y^2)

=(x-3y)^2+y(x+3y)(x-3y)

=(x-3y)[x-3y+y(x+3y)]

=(x-3y)(x-3y+xy+3y^2)