劳拉·威金斯后入:分解因式a^3+3a-76 要过程

来源:百度文库 编辑:中科新闻网 时间:2024/04/29 10:13:22

根据因式定理,可能的因式有
a+1,a-1,a+2,a-2,a+4,a-4,a+19,a-19,a+38,a-38,a+76,a-76

当a=4时原式得0,因此原式含有因式a-4
原式除以a-4,得a2+4a+19
因此原式=(a-4)(a2+4a+19)

方法二:
原式=a^3+3a-76
=a^3-4a^2+4a^2-16a+19a-76
=a^2(a-4)+4a(a-4)+19(a-4)
=(a-4)(a^2+4a+19)

a^3+3a-76
=a^3-4a^2+4a^2-16a+19a-76
=a^2(a-4)+4a(a-4)+19(a-4)
=(a-4)(a^2+4a+19)

a^3+3a-76
=a^3-64+3a-12
=(a-4)(a^2+4a+16)+3(a-4)
=(a-4)(a^2+4a+19)