x-3y=2 2x+y=18 求xy
已知3x*+xy-2y*=0,求(x/y)-(y/x)-(x*+y*)/(xy)的值.*是平方
已知xy=-2,x-y=3,求(x+y)(x-y)-y^2+(x-y)^2-(6x^2y-2xy^2)÷2y
已知3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)}
已知3/(x-y)=1/xy 求(-x-2xy+y)/ (2x+3xy-2y)
若(y-x)/xy=3,求分式(2x+3xy-2y)/(x-2xy-y)的值
已知x-y/xy=3,求分式2x+3xy-2y/x-2xy-y的值.
若y-x/xy=3,求分式2x+3xy-2y/x-2xy-y
已知xy/x+y =3,求2x-3xy+2y/-x+3xy-y 的值.
已知xy/x+y=3,求2x-3xy+2y/-x+3xy-y的值
已知X+Y=3XY,求2X+2Y-XY除以X+Y+2XY的值,要算理.
已知x-y=4xy,求x-2xy-y分之2x+3xy-2y的值!
已知x+y=3xy,求2x+2y-xy/x+y+2xy的值、