1/(x2-2xy+y2)+1/(x2+2xy+y2)=1.那位懂的帮帮忙.
1,1,X2-1-2xy+y2
在x2+2xy-y2,-x2-y2+2xy,x2+xy+y2,4x2+1+4x中,能用完全平方公式分解因式的有( )个
已知x2+4y2+x2y2-6xy+1=0,求 x4-y4/2x-y 乘 2xy-y2/xy-y2 除以(x2+y2/x
如果x2+xy=2,xy+y2=-1,则x2-y2=______,x2+2xy+y2=______.
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
x2+2y2-2xy-2y+1=0
已知x-y+1,X2+Y2=25 求(x+y)2和x2-xy+y2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
已知x(x-1)-(x2-y)=-3,求x2+y2-2xy的值
已知x2-xy=-3,2xy-y2=-8,求2x2+4xy-3y2的值.
已知x2+xy=3,xy+y2=-2,则2x2-xy-3y2的值为( )