Question

已知x-2y=1,xy=-2求代数式4x^2y^4-4^3y^3+x^4y^2的值

Answer 1

4x^2y^4-4x^3y^3+x^4y^2

=x^2y^2(4y^2-4xy+x^2)

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

=(-2)^2(1)^2

=4