x^2-3ax+(2a+1)(a-1)
问题描述:
x^2-3ax+(2a+1)(a-1)
答
x^2-3ax+(2a+1)(a-1)
=x^2-(2a+1+a-1)x+(2a+1)(a-1)
=(x-2a-1)(x-a+1)
十字相乘法