27的最后两小问怎么做,求解,谢谢,急!
2个回答
展开全部
165
解析:
a⁴+13b²
=(3a+2)²+13b²
=(9a²+12a+4)+13b²
=(9a²+4)+12a+13b²
=(9a²+4)+4(a²-2)+13b²
=13a²+13b²-4
=13[(a+b)²-2ab]-4
=13[3²-2(-2)]-4
=13²-4
=165
解析:
a⁴+13b²
=(3a+2)²+13b²
=(9a²+12a+4)+13b²
=(9a²+4)+12a+13b²
=(9a²+4)+4(a²-2)+13b²
=13a²+13b²-4
=13[(a+b)²-2ab]-4
=13[3²-2(-2)]-4
=13²-4
=165
追问
最后一问捏
追答
a^5+b^5
=a(3a+2)²+b(3b+2)²
=a(9a²+12a+4)+b(9b²+12b+4)
=a[9(3a+2)+12a+4]+b[9(3b+2)+12b+4]
=a(39a+22)+b(39b+22)
=39(a²+b²)+22(a+b)
=39[(a+b)²-2ab]+22(a+b)
=39[3²-2×(-2)]+22×3
=573
推荐律师服务:
若未解决您的问题,请您详细描述您的问题,通过百度律临进行免费专业咨询