15 7x 3 x July 8, 2019 16 32 64 128 15 7x 3 3x 7x 15 4 x 3 7x 15 4x 3 x 3 X 2 7x 15 x 3 7x 15 3 3x 7 15 7x x 1 3 2x 2 7x 15 x 3 15 x 3 7x simplified
