{5x-2y-2=0、2x-2y-7/5 方程组怎么解?

解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7 x*x+2x+y*y-4y+5=0 x= y= {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 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 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 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 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 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 先化简,再求值 [2/3x - 2/x+y（x+y/3x -x-y）]*x/x-y,其中5x+3y=0 先化简,再求值:[3x-2/x+y(x+y/3x-x-y)]/(x-y/x),其中5x+3y=0 已知7x+5y/2y-x=3/2,且x≠0,求X/x-4y 3x+5y-(x+y)=6 2(x+y)-3x=-7 x*x+y*y-2x+4y+5=0求x, .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 x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x 2(x-y)=5y,x-y=-5