log4(768) = log4(4^3 * 3) = log4(4^3) + log4(3) = 3 + log4(3) = 3 + log(3)/log(4) ≈ 3 + 0.7925 ≈ 3.7925

log4(12) = log4(4*3) = log4(3) + log4(4) = log(3)/log(4) + 1 = 0.7925 + 1 = 1.7925

Итак, log4(768) - log4(12) ≈ 3.7925 - 1.7925 = 2