elvissarog

a) = (2^2n) / (2^2n-2) = 2^2 = 4;

b) = (6^2n * 7^2n * 3^2-2n) / 2^2n+1 * 7^2n = 3^2n*3^2-2n / 2 = 3^2/2 = 9/2 = 4,5.