4y2-(x2+y)+(x2-4y2),其中x=-28 y=
4y2-(x2+y)+(x2-4y2),其中x=-28 y=
已知方程x2 +y2+4x-2y-4=0,求x2 +y2的最大值
已知x2+4x+y2-2y+5=0,则x2+y2=______.
1.已知X2+Y2-4X-6Y+13=0,求Y2-X2的值
已知x2-4x+y2-6y+13=0求x2+y2的值?
已知x2+y2+4x-6y+13=0 求x2-2x\x2+3y2
X2+Y2+8X+6Y+25=0 求代数式(x2-4y2/x2+4xy+4y2)-x/x+2y
已知X2+Y2+8X+6Y+25=0 求代数式X2++XY+4Y2分之X2-4Y2 减X+2Y分之X的值
已知x2+y2+4x-6y+13=0
已知实数x,y满足x2+y2-2x+4y=0,则x2+y2的最小值是
已知x2+4y2+x2y2-6xy+1=0,求 x4-y4/2x-y 乘 2xy-y2/xy-y2 除以(x2+y2/x
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值