Question

已知XY²=-2,求代数式（XY)(X³Y的七次方-3X²Y的5次方-5Y)

Answer 1

xy(x^3y^7-3x^2y^5-5y)

x^4y^8-3x^3Y^6-5xy^2

=(xy^2)^4-3(xy^2)^3-5xy^2

=(-2)^4-3(-2)^3-5(-2)

=16+24+10

=50