已知x+y=4,xy=2,求2x^3y+4x^2y^2+2xy^2的值
问题描述:
已知x+y=4,xy=2,求2x^3y+4x^2y^2+2xy^2的值
答
2x^3y+4x^2y^2+2xy^2
=2xy(x²+2xy+y²)
=2xy(x+y)²
=2*2*4²
=64