已知x^2y=3,求2xy(x^5y^2-4x)的值
问题描述:
已知x^2y=3,求2xy(x^5y^2-4x)的值
答
2xy(x^5y^2-4x)
=2xy*x^5y^2-2xy*4x
=2x^6y^2-8x²y
=2(x²y)³-8x²y
=2×27-8×3
=30