2X%+Y%=1.5 2\X+7\Y=30、、、、、、、、、、、、X=?,Y=?

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 (x-y)(x-2y)+(x-2y)(x-7y),其中X=4,Y=1.5 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一 已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) 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)=? [3x^2-(x+y)(y-x)][2(-x-y)(y-x)+2x^2+3y^2],其中x=-2分之1,y=1.5 [(x-y)²+（x+y）(x-y)]/2xx=3,y=-1.5 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 3x+5y-(x+y)=6 2(x+y)-3x=-7 化简:【(x-y)的2次方+(x+y)(x-y)】除以2x,其中x=3,y=1.5 先化简,后求值:[(x-y)²+(x+y)(x-y)]÷2x,其中x=3,y=1.5 x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x