N 2 3n 12 July 8, 2019 16 32 64 128 N 2 3n 12 6 solve by factoring N 2 3n 12 0 N 2 3n − 12 6 N 3 3n 2 2n 120 N 3 3n 2 2n 120 0 N 2 3n 5 chia hết cho 121 Factor n 2 3n 12 6 6n 2 n 12 )/( 3n 4 N 2 3n 4 5n 6 12 3n 2 n 1200 3n 2 n 2 9n 12 N 5n 12 3n 2 25 2 3n for n 12
