x+y=36；x-（y-x）=3/4x. 怎样算

3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 （x+y）/2- x-y/2=6 3(x+y)=4(x-y) (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= x+y=36；x-（y-x）=3/4x. 怎样算 y(x+y)+(x-y)²-（x+y）（x-y）,其中x=-1/3,y=3 x/3=y/4,求(x*x-xy)/(x*x+y*y)的值 已知（x+y）2 =2,(x-y)3 =3,求(x+y)7(x-y)2(x+y)3(y-x)4 的值 若x+y=4,则多项式1/2(x+y)+4(x-y)-3（x-y）-3/2(x+y)-x+y值是（） x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做. （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 {3(x+y)+3(y+x)=1,3(x+y)+4(y-x)=-1 2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15 （3x-y)(y+3x)-(4x-3y)（4x+3y)=? {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 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