5X+（y-x)=(5+1)(y-x)求答案·并公式~

(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 {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 1/x-1/y=x,求5y+xy-5y/y-xy-x=? 求(X+Y)(X-Y)(X²+Y²),X=5 Y=2, 已知：4x = 5y,求(x+y) ：y 求y=(5x-1)/(4x+2) (x x+y=1/5x²+y²=1求x、y 4x-3y=5 x^2+y^2=1 求x,y 3x+4y-5=0 x^2+y^2=1求x.y x+y=8 2x-y=1 求3x+5y 已知:2x-y/x+y=1/5,求2x+5y/6x-2y的值 已知x>0,y>0,2/x+5/y=1,求x+y最小值 已知x-y=1,求x平方-y平方+3x-5y的值 x^2-x+y^2+2y+5/4=0 求x^-1+y^0 已知x+y=-1,xy=-2,求代数式-5（x+y)+(x-y)+x(xy+y)的值 x,y都大于零,若x+y=5,求(x+1/x)(y+1/y)的最小值?