x2-3xy-10y2+x+9y-2xy后面的2是平方 最后个二是减2 谢谢个位大哥大姐帮忙做下 不要就一个答案

计算(x+y/x-y + 4xy/y2-x2)(x2-9y2)/（x2+2xy-3y2） (3xy-9x2-2y2-6xy)-(6x2+2xy-3xy-y) 因式分解2x2-7xy-22y2-5x+35y-3 x2-3xy-10y2+x+9y-2 x2-4y2-3xy+y+x (x-y)(x2+xy+y2) (x+y)(x2-xy+y2) 解方程组 ｛3x2-y2=8 {4x2+12xy+9y2=1 {x2+2xy+y2-4=0 x2+xy+y2=4 4x2-9y2=0 x2-2xy+y2-1=0还有{x2+y2=4xy-y2+4=0x2-----x的平方 y2------y的平方 还有{2x-3y=12x2-3xy+y2-4x+3y-3=0 25(x2+ 2xy +y2)-9(x2-2xy+y2)因式分解.x2,y2是x平方,y平方的意思.2xy就是2xy.快, 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 因式分解3x2+xy-y2+x+9y-43X^2+XY-Y^2+X+9Y-4 x2+2xy-3y2+3x+y+2 因式分解 因式分解x2+2+y2-3x-2xy+3y 因式分解2y2-xy-3x2-2y+3x 2x2+xy-3y2+x+4y-1因式分解 4x2-y2/x2-2xy+y2 +(2x-y)/2x2-2xy 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 x2-2xy-3y2=0,其中x,y均不为零,求（y-x）/x2-xy/2x-y-y2/xy-x x2+2xy+y2-9=0 (x-y)2-3(x-y)+2=0