Question

упростите (x-3y)(x-3y)(x2+9y2)

Answer 1

$(x-3y)(x-3y)(x^2+9y^2)= (x-3y)^2(x^2+9y^2)=(x^2-6xy+9y^2)(x^2+9y^2)=x^4+9x^2y^2-6x^3y-54xy^3+9x^2y^2+81y^4$