64-x^2×^2-16y^2a^2-y^24x^2-9a^21-4b^216-b^2m^2-25b^2 1-49n^2100-64k^2-25x^2+16a^2
(8-х)(8+х)
(х-4у)(х+4у)
(а-у)(а+у)
(2х-3а)(2х+3а)
(1-2b)(1+2b)
(4-b)(4+b)
(m-5b)(m+5b)
(1-7n)(1+7n)
(10-8k)(10+8k)
(5x-4a)(5x+4a)