(3a²-4a+5)(3a²+4a-5)-a²(9a²-16)
问题描述:
(3a²-4a+5)(3a²+4a-5)-a²(9a²-16)
答
(3a²-4a+5)(3a²+4a-5)-a²(9a²-16)=[3a²-(4a-5)][3a²+(4a-5)]-a²(9a²-16)=9a^4-(4a-5)²-9a^4+16a²=16a²-(4a-5)²=(4a+4a-5)(4a-4a+5)=5(8a-5)=40a...