4a + 1)^2 * (4a - 1)^2 = (16a^2 + 1)^2 - 64a^2
(16a^2 + 8a +1) * (16a^2 - 8a + 1) = 256a^4 + 32a^2 1 - 64a^2
256a^4 - 128a^3 + 16a^2 + 128a^3 - 64a^2 + 8a + 16a^2 -8a + 1 = 256a^4 - 32a^2 + 1
256a^4 - 32a^2 + 1 = 256a^4 - 32a^2 + 1
256a^4 - 32a^2 + 1 -256a^4 + 32a^2 - 1 = 0