x+y=90 5/8x＋5＝3／5y　　x,y分别是多少?

（x+y-5)*（x+y-5)+（x-y+3)=0 x*x-y*y 已知:3x-5y=0,求x/y,x-y/y,x-y/x x+y=90 5/8x＋5＝3／5y　　x,y分别是多少? 若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×Y＝ 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) (2x+y)²+(x+3y)(x-3y)-x(5x+8y)因式分解 3x(2x＋y)－2x(x-y),其中x＝1,y=1/5 [2(x-y)^5-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2[2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 3x-2y=9 x-3y=2 x+y=5 x+2y=3 y=x 2x+y=8 x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x 已知x.x+y.y-6x-8y+25=0,求3x.x+5y的值 先化简,再求值.2(x-2y)^2+8(x-2y)-3(2y-x)^2+5(2y-x),其中-x+2y=-3RT为什么-3(2y-x)^2＝3(x-2y)²? (3x-4y)(5x-4y)-(7x-8y)(6y-5x) （5x+3y)(3y-5x)-(4x-y)(4y+x)= 5(x-y)^2-(x-y)-8(x-y)^2-3(x-y) (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11