（5*x+2*y）/(x+y)=3,求x与y的关系,是不是x=2y?怎么算?读作：5乘以x+2乘以y的和除以x+y的和等于3

已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 已知:3x-5y=0,求x/y,x-y/y,x-y/x 若x-y分之x+y=3,求式子x+y分之5(x-y)—2（x-y）分之x+y的值 {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 5X+Y=3 X+5Y=2 求x和y.5X+Y=3X+5Y=2求x和y. 已知x=2,y=3,求代数式（x-y）*（x-y）^3*(x-y)^5*……*(x-y)^11 已知（x+2）^2+|x+y+5|=0,求3x^2y-[2x^2y-(2xy-x^2y)-4x^2]-xy 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 已知3x =2y 求x/x+y+y/x-y-y²/x²-y² 若x-y/x+y=5,求x-y/2x+2y+5x+5y/3x-3y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分之x-y=3,求式子x+y分之5(x-y)—2(x-y)分之x+y的值 x+y分之x-y=-2,求3（x+y)分之x-y减去x-y分之2（x+y）的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 y=x^3-5x^2+2x-8 求y^2求y撇 6x+5Y=31 2X+3Y=17求X求 Y 求(X+Y)(X-Y)(X²+Y²),X=5 Y=2,