分解因式:x2+3x(x-3)-9=_.
问题描述:
分解因式:x2+3x(x-3)-9=______.
答
x2+3x(x-3)-9
=x2-9+3x(x-3)
=(x-3)(x+3)+3x(x-3)
=(x-3)(x+3+3x)
=(x-3)(4x+3).
故答案为:(x-3)(4x+3).