先化简再求值,(-4x^2)/(-2x)+12x^3y^2/(-4x^2y)-24x^4y^3/(-4x^3y^2),x=-2,y=1/4
问题描述:
先化简再求值,(-4x^2)/(-2x)+12x^3y^2/(-4x^2y)-24x^4y^3/(-4x^3y^2),x=-2,y=1/4
答
(-4x^2)/(-2x)+12x^3y^2/(-4x^2y)-24x^4y^3/(-4x^3y^2)
=2x-3xy+6xy
=2x+3xy
=x(2+3y)
= (-2)*(2+3/4)
= -2*11/4
= -11/2