已知x(x-1)-(x2-y)=-2求x2+y2-4xy的值
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
已知x(x-1)-(x2-y)=-3,求x2+y2-2xy的值
已知x-y+1,X2+Y2=25 求(x+y)2和x2-xy+y2的值
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:x-2y=12,xy=-25,求x2+4y2-1的值?
已知x+y=4,xy=2,求x2+y2+3xy的值.
已知x2+y2=20,x2+xy-2y2=2(x+2y),求x+y的值
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X2-2x+y2+6y+10=0,求(x2-2xy)/(xy+y2)的值
已知x2-3xy-4y2的绝对值+2倍根号x2+4xy+4y2-1=0 求3x+6y的值
x(x-1)-(x2-y)=-3,求x2-y2-2xy的值
x(x-1)-(x2-y)=-3,求x2+y2-2xy的值