FACTOR COMUN :
8 × 2 + 8 × 18 = 8 × ( 2 + 18 ) = 8 × 20 = 160
7 × 8 + 3 × 8 = ( 7 + 3 ) × 8 = 10 × 8 = 80
5 × 11 + 11 × 8 = 11 × ( 5 + 8 ) = 11 × 13 = 143
6 × 15 + 15 × 4 = 15 × ( 6 + 4 ) = 15 × 10 = 150
8 × 5 - 8 × 3 = 8 × ( 5 - 3 ) = 8 × 2 = 16
9 × 8 - 6 × 9 = 9 × ( 8 - 6 ) = 9 × 2 = 18
4 × 15 - 4 × 1 = 4 × ( 15 - 1 ) = 4 × 14 = 56
8 × 12 - 8 × 6 = 8 × ( 12 - 6 ) = 8 × 6 = 48