几道因式分解-3a的(n-1)次方+6a的n次方-12a的（n+1）次方（n为大于1的正整数）若n为正整数,求证3的（n

x^+x-4y^-2y = x^-(2y)^ +x-2y = (x-2y)(x+2y) +x-2y = (x-2y)(x+2y+1)
m^-4n^-3m+6n = (m+2n)(m-2n) -3(m-2n) = (m-2n)(m+2n-3)
a^-4a+4-b^ = (a-2)^ - b^ = (a+b-2)(a-b-2)
x^-y^-2y-1 = x^ -(y^+2y+1) = x^ -(y+1)^ = (x+y+1)(x-y-1)
4a^-b^+4a+1 = (2a+1)^ -b^ = (2a+b+1)(2a-b+1)
a^b^-2ab-15 = (ab - 5)(ab + 3)
x的4次方-8x^-9 = (x^ -9)(x^+1) = (x-3)(x+3)(x^+1)
x^+5x+6 =(x+3)(x+2)
x^-5x-6 = (x-6)(x+1)
x^+5x-6 = (x+6)(x-1)
x^y^-5x^y+6x = x(xy^ - 5xy +6)
-x^-2x+3 = -(x-1)(x+3)
不错吧!给点分!

x^+x-4y^-2y = x^-(2y)^ +x-2y = (x-2y)(x+2y) +x-2y = (x-2y)(x+2y+1)
m^-4n^-3m+6n = (m+2n)(m-2n) -3(m-2n) = (m-2n)(m+2n-3)
a^-4a+4-b^ = (a-2)^ - b^ = (a+b-2)(a-b-2)
x^-y^-2y-1 = x^ -(y^+...