2x-3y=2 （2x-3y+5)/7+2y=9 这样总可以了吧

已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 3x+5y-(x+y)=6 2(x+y)-3x=-7 x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 化简:3(x-y)²-7(x-y)+ 2(x-y)²+5(x-y) (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 计算(x^8-x^7y+x^5y^3-x^4y^4+x^3y^5-x^y^7+y^8)(x^2+xy+y^2) 先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5 化简3(x-y)-7(x--y)+2(y-x) 化简:5(x-y)+2(x+y)-3(x-y) 把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)= 3(x-y)把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)=3(x-y)²-4(x-y)+7(x-y)-6(x-y)²= {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)=