3x-y+x=3 4【X-y-1】=3【1-y】-1 5x-4y+4x=3 2x+y-3x=11 【 x除以2 】-【y 除以3】 =2 2x+7y-3x=19 x+y+x=12 3x+2y-x=18

{3(x+y)+3(y+x)=1,3(x+y)+4(y-x)=-1 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= x+y+2(-x-y+1)=3(1-y-x)-4-(y+x-1),x+y=? 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 先化简 再求值 (2x-y)(y+x)-(x-2y)(2y+x)-(-3y+x)^2其(√x+1)+y^2+4=-4y 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 已知x-y=1,求[(x+2y)^2+(2x+y)(x-4y)-3(x+y)(x-y)]除以y的值大神们帮帮忙 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 y(x+y)+(x-y)²-（x+y）（x-y）,其中x=-1/3,y=3 9y=3x-(x-1),4(x+y)-(2x+4)=8y 若(-x+6):(x-y):(4x+y)=3:14:1,求x+y 若(-x+6):(x-y):(4x+y)=3:14:1,求x+y (-x+6):(x-y);(4x+y)=3;14:1,求x+y的值. （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 4x(x-y)-(2x-3y)(2x-3y) x=1 y=-1 推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做.