-﹙x2+y2﹚+[﹣3xy-﹙x2+y2﹚]

-﹙x2+y2﹚+[﹣3xy-﹙x2+y2﹚] x2-4y2-3xy+y+x (x-y)(x2+xy+y2) (x+y)(x2-xy+y2) 计算(x+y/x-y + 4xy/y2-x2)(x2-9y2)/（x2+2xy-3y2） 已知y/x=1/2,求(x2+2xy+y2)/﹙x2-xy-2y2)的值. (3xy-9x2-2y2-6xy)-(6x2+2xy-3xy-y) 已知实数x,y满足x2+xy+y2=3,则x2-xy+y2的最小值 因式分解x2+xy-3y2 X2+3xy+y2因式分解 解方程组①x2-y2=3x+3y②x2-xy+y2=27 如果2/x=3/y,那么x2-2xy+3y2/7x2-y2? (x2+xy+y2)-4xy(x2+y2) 4x2-3y2+2xy-4x2+5x2 4x2-y2/x2-2xy+y2 +(2x-y)/2x2-2xy 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