解{x-2y=0{5x-7y-2=0

解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7 x*x+2x+y*y-4y+5=0 x= y= 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 解方程（y-x-5)y'-y+2=0 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? {2x+y/3-2y=0 2(2x+y)-5=7y 如果方程组x-y=a-3,2x+y=5的解x、y满足x>0,y 已知(x-y)^2+|5x-7y-2|=0,求x,y的值. 已知|5x-y-8|+(7y-x+2)=0则4x+6y 7y(x-3y)-2(3y-x)=0 .x=?,y=? 先化简,再求值 [2/3x - 2/x+y（x+y/3x -x-y）]*x/x-y,其中5x+3y=0 已知7x+5y/2y-x=3/2,且x≠0,求X/x-4y 先化简,再求值:[3x-2/x+y(x+y/3x-x-y)]/(x-y/x),其中5x+3y=0 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 x*x+y*y-2x+4y+5=0求x, 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) .先化简再求值：（2x+y）（2x+y)-(2x-y)平方其中X,Y满足X平方+Y平方-2X+4Y+5=0