【1/2xy+y2+1】+【x2-1/2xy-2y2-1】等于多少
1,1,X2-1-2xy+y2
已知x2+4y2+x2y2-6xy+1=0,求 x4-y4/2x-y 乘 2xy-y2/xy-y2 除以(x2+y2/x
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
如果x2+xy=2,xy+y2=-1,则x2-y2=______,x2+2xy+y2=______.
x2+2y2-2xy-2y+1=0
因式分解:x3+(y-1)x2-2xy-y2
2x2+xy-3y2+x+4y-1因式分解
先化简,再求值:(1)2x2-5x x2 4x,其中x=-3 (2)(3x2-xy-2y2)-2(x2 xy-2y2),
已知x-y+1,X2+Y2=25 求(x+y)2和x2-xy+y2的值
先化简再求值:-(x2+y2)+[-3xy-(x2-y2)],其中x=-1,y=2.
已知x2-2xy=3y2且x,y为非零实数 求:(1)2x+y/x-2y (2)2x2-3y2+5xy/x2+xy+y2
先化简再求值2(x2-xy)-3(2x2-3xy)-2[x2-(2x2-xy+y2)],其中x=-1,y=-2.