(-3a-4b)()=9a^2-16b^2 急
问题描述：
(-3a-4b)()=9a^2-16b^2 急
答
(-3a-4b)(-3a+4b)=9a^2-16b^2
(9a²-16b²)/(-3a-4b)
=[(3a+4b)(3a-4b)]/[-(3a+4b)]
=-(3a-4b)
=-3a+4b