(5a-3b)(5a+3b)(25a²-9b²),(2a²-3b+4c)(2a²+3b-4c),
问题描述：
(5a-3b)(5a+3b)(25a²-9b²),(2a²-3b+4c)(2a²+3b-4c),
答
原式=(25a²-9b²)²
=625a^4-450a²b²+81b^4
原式=[2a²-(3b-4c)][2a²+(3b-4c)]
=(2a²)²-(3b-4c)²
=4a²-9b²+24bc-16c²