9x²+6xy+y²-14(3x+y)+49
(x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)
x²/xy-x/y
化简:x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y)
计算:(xy-x²)×x-y/xy
4x²+2x-9y²+3y,x²+6y-y²-9,x²-xy-2y
已知x/y=2,求x²-xy+3y²/x²+xy+6y²的值
初二数学通分问题2x+6y/x—3y和x/x—9y²和1/x²6xy+9y²
求通分 2x+6y/x-3y,x/x-9y²,1/x²-6xy+9y²
先化简,在求值9x³-xy²/(3x+y)(9x²-6xy+y²)其中x=1,y
有三道因式分解1.x²-6xy+9y²-3x+9y+2,
(3x+2y)(9x²-6xy+4y²﹚
用公式计算(2y-3x)(4y²+6xy+9x²﹚