(3xy-9x2-2y2-6xy)-(6x2+2xy-3xy-y)

(3xy-9x2-2y2-6xy)-(6x2+2xy-3xy-y) 化成最简分式:6x2-7xy-3y2分之2x2+xy-6y2 x2-2xy+y2-9 已知6x2减去xy减去15y2等于0,求分式2x2减去3xy减去3y2分之x2减去2xy+4y2 若2分之x=3分之y,求x2-6xy-7y2分之x2-2xy-3y2 若x/y=2,求x2-2xy-3y2/x2-6xy-7y2的值 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） 已知x2+4y2+x2y2+1=6xy,则(x4-y4)/(2x2+xy-y2)*(2x-y)/(xy-y2)/(x2+y2/y)2= 求证:(x2-xy+y2)3+(x2+xy+y2)3能被2x2+2y2整除 若X2+xy-2y2=0,则（x2+3xy+y2)/x2+y2=? 2(x2-xy)-3(2x2-3xy)-2[x2-(2x2-xy+y2)] 化简. 分解因式 （1）32+5xy-2y2+x+9y-4 （2）2x2+xy-y2-4x+5y-6 (3)3x2+4xy-y2 已知x2+xy=3,xy+y2=-2,则2x2-xy-3y2= 已知x2-3xy=-5,xy+y2=3,求x2-2xy+y2. x2-2xy+y2=4 x2+y2-x-y=6 解不等式x2-2xy+y2=4 x2+y2-x-y=6 解不等式 分解因式：4x2-12xy+9y2-2x+3y-6 2(x-xy)-3(2x2-3xy）2[x2（2x2-xy+y2)]