(π-1)(a-1)+3(1-a)的2方
问题描述：
(π-1)(a-1)+3(1-a)的2方
答
(π-1)(a-1)+3(1-a)^2
=(π-1)(a-1)+3(a-1)^2
=[(π-1)+3(a-1)](a-1)
=(π-1+3a-3)(a-1)
=(π+3a-4)(a-1)