因式分解 (x-1)(x-3)+1 ab+a+b+1

问题描述:

因式分解 (x-1)(x-3)+1 ab+a+b+1

(x-1)(x-3)+1
=x²-4x+3+1
=x²-4x+4
=(x-2)²
ab+a+b+1
=(a+1)(b+1)