化简求值:根号x^-2xy+y^2 + x^2 -6xy+9y^2/x-3y,其中x=根号3,y=根号5

问题描述:

化简求值:根号x^-2xy+y^2 + x^2 -6xy+9y^2/x-3y,其中x=根号3,y=根号5

√x^-2xy+y^2 + x^2 -6xy+9y^2/x-3y
=√(x-y)^2+(x-3y)^2/x-3y 由于y>x
=y-x+x-3y
=-2y
=-2√5