y2-x2/5x2-4xy除以x+y/5x-4y点做?

y2-x2/5x2-4xy除以x+y/5x-4y点做? 已知x2+y2+4x-2y+5=0,求x2+2xy+y2值 2x2+xy-y2-4x+5y-6 因式分解 已知2+4y2-4x+4y+5=0,求x四次方-y的四次方/xy乘以2x2-xy/xy-y2除以(y分之x2+y2)2 因式分解：3x2+5xy-2y2+x+9y-4 x2+x-(a2-a) 3x2+4xy-y2 x,y,a后面的2表示平方 x2-4y2-3xy+y+x (x-y)(x2+xy+y2) (x+y)(x2-xy+y2) 4x2-y2/x2-2xy+y2 +(2x-y)/2x2-2xy 已知x2+y2,x-y=5,求x2+y2和xy的值. X2+xy-12y2-2x+27y+5因式分解 x2-xy-2y2-x+5y-2 x2-xy-2y2-x+5y-2因式分解 x>y>o xy=2 求证 (x2+y2)除以x-y大于等于4 因式分解 2x2+xy-y2-4x+5y-6 x2-y2+a2-b2+2ax+2by 3x2+5xy-2y2+x+9y-4 b4-2b2-82x2+xy-y2-4x+5y-6x2-y2+a2-b2+2ax+2by3x2+5xy-2y2+x+9y-4b4-2b2-8 计算(x+y/x-y + 4xy/y2-x2)(x2-9y2)/（x2+2xy-3y2） x+y=3,xy=-5,x2+y2=19,x2-xy+y2=24,求x-y 4x2-3y2+2xy-4x2+5x2