已知x-3y=2x+y-15=1,则x^2-4xy+y^2

已知x-y=4xy，则2x+3xy-2yx-2xy-y 已知x-3y=2x+y-15=1,则x^2-4xy+y^2 已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y= 已知3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)} 已知：x-y=1,xy=-2.求：(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 .已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 已知x-y=3,xy=1,求（-2x+2x+3y)-(3xy+2y-2x)-(x+4y+xy) 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 已知x-y=1,则x^4-x^3y-xy^3-3x^2y+3xy^2+y^4= 已知1/x=1/y=6,则3x-2xy+3y/3xy+x+y=? 已知1/x减1/y=-3,则(2x+xy-2y)/x-xy-y的值为 已知1/x-1/y=3,求(3x+4xy-3y)/(x-2xy-y)的值