(9x^2+4y^2)(3x+2y)(3x-2y)
问题描述:
(9x^2+4y^2)(3x+2y)(3x-2y)
答
(3x+2y)(3x-2y)
=(9x^2-4y^2)
所以
(9x^2+4y^2)(3x+2y)(3x-2y)
=(9x^2+4y^2)(9x^2-4y^2)
=81x^4-16y^4