3^(4n+2) can be written as 3^4n * 3^2 = 9 * 3^4n. For all n = 0, 1, 2, 3 ..., the units digit of 3^4n is 1. n=0; 3^0 -> units digit is 1 n=1; 3^4 -> units digit is 1 n=2; 3^8 -> units digit is 1 ... => the units digit of 9 * 3^4n is 9, to which when 1 is added the units digits would be 0, which is c...