求y=1／2x^2-x+1和y=（x-1）（x-5）顶点坐标

已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 2x+4y=3 -3x-2y=1 ..求x和y 2x+y=1,25x+2y=-40,求x和y? x+2y=2x+y+1=7x-y 求：2x-y? (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 若x*x+y*y=x+y-1/2,求x,y的值如题 若x.y满足x+=4和x-y=2,求xy分之2x-y+1除以-x分之y+y分之x的值 {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? x+y=1,xy=-1/2,求x(x+y)(x-y)-x(x+y)2 三分之x-2y-二分之x+2y=-1,5(x-2y)-4(x+2y)=-1求x和y的值 已知实数x,y满足方程x^2+y^2-4x-2y+1=0.求x^2+y^2+x+y的最大值和最小值. 若x,y∈R,(x+y)^2i+6i-x=-y+5(x+y)i-1,求x和y的值 已知:【(x²+y²)-(x-y)²+2y(x-y)】/4y=1,求4x/4x²-y²-1/2x+y 已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) 已知x-y=1,求[(x+2y)^2+(2x+y)(x-4y)-3(x+y)(x-y)]除以y的值大神们帮帮忙 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 已知x+2y=2x+y+1=7x-5,求x和y的值