分解因式：①x^2+3y-xy-3x②x^3+2x^2y-9x-18y③(y+2)x^2+(y+2)x-12y-24
问题描述：
分解因式：①x^2+3y-xy-3x②x^3+2x^2y-9x-18y③(y+2)x^2+(y+2)x-12y-24
④m平方x平方+n平方y平方-n平方x平方
答
①x^2+3y-xy-3x=x(x-y)-3(x-y)=(x-y)(x-3)②x^3+2x^2y-9x-18y=x²(x+2y)-9(x+2y)=(x+2y)(x²-9)=(x+2y)(x-3)(x+3)③(y+2)x^2+(y+2)x-12y-24 =(y+2)x²+(y+2)x-12(y+2)=(y+2)(x²+x-12)=(y+2)(x+4)(x...