y=-2x x+y=8 3x-y=10 x+y=0 -2x+7x=24 3x-2y=4 2y-5x=12 2x-x=3x

已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y 先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5