由已知可得:5x-2y=5x-4y=1,解得:x=1y=0,
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?
已知x²+y²+5=2x+4y,求代数式(2x²-(x+y)(x-y))x((x+y-1)
已知X,Y,满足(X+3Y)(X-3Y)=-10(Y^2-6/5)和2X(Y-1)+4(1/2X-1)=0
已知4x=9y求(1)x+y/y (2)y-x/2x
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
由y=x^2+4\x^2+1得x^2=y+4\y+ 1
用代入法解方程组3x+4y=2,2x-y=5使得带入后化简比较容易变形是()1.由1得,x=2-4y/3 2.由1得y=
已知x方+y方-4x+1=0求y-x得最大值(^_^)
已知x^2+4y^2-4x+4y+5=0,求(y^4-x^4)/(y-2x)(x+y)*2x-y
已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值