5a(a^2+2a+1)-a(a-4)(5a-3),其中a=-2
问题描述：
5a(a^2+2a+1)-a(a-4)(5a-3),其中a=-2
答
5a(a²+2a+1)-a(a-4)(5a-3)
=5a³+10a²+5a-a(5a²-23a+12)
=5a³+10a²+5a-5a³+23a²-12a
=25a²-2a
∵a=-2
∴原式=25×(-2)²-2×(-2)
=100+4
=104