7/x-2y+2/=-15(3x+2y-4)^2 则(x+y)^2= 多少

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 x^2+y^2=15,x+y=7,x＞y,求x-y 2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 化简3(x-y)-7(x--y)+2(y-x) (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) (x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) (x+y)(2x-3y)=? 7y(x-3y)-2(3y-x)=0 .x=?,y=? 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 已知3x =2y 求x/x+y+y/x-y-y²/x²-y² x(x-y)2-(y-x)3 3x+5y-(x+y)=6 2(x+y)-3x=-7 已知（x+y）2 =2,(x-y)3 =3,求(x+y)7(x-y)2(x+y)3(y-x)4 的值 x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x