3y+12=x 4y+5=x ,求x,y

已知:3x-5y=0,求x/y,x-y/y,x-y/x 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 3y+12=x 4y+5=x ,求x,y 5x+y=12 x-3y=4 求x和y 已知：4x = 5y,求(x+y) ：y (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) x(x-3y)=4y(x-3y),求x:y 已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y除以2x-y 已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y/2x-y的值 已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y/2x-y的值 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 21/(x+y)+4/(x-y)=12/(x+y)+7/(x-y)结果为(x+y)/(x-y)=3求过程! 已知关于x、y的方程组3x+5y=4 5x+3y=12 求x+y与x-y的值. {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? |x|=3 |y|=5 |x-y|=|x|+|y| 求 X+Y和 X-Y 等于多少 已知2y-x=-3,求[4y(2x-y)-2x(2x-y)]/(2x-y x/3=y/4,求(x*x-xy)/(x*x+y*y)的值 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值