(a+1)(a+2)(a+3)(a-6)怎么算?不死算的方法!
问题描述:
(a+1)(a+2)(a+3)(a-6)怎么算?不死算的方法!
答
(a+1)(a+2)(a+3)(a-6)
=[(a+1)(a-6)] [(a+2)(a+3)]
=(a²-5a-6)(a²+5a+6)
=(a²)²-(5a+6)²
=a^4-25a²-60a-36