Answer:
17a - 3b
Step-by-step explanation:
12a + 8b + 6a - 9 b - a - 2b••••••••• ( distribution property over bracket to remove this bracket )
12a + 6a - a + 8b - 9b - 2b•••••••••••• ( collected like terms )
17a + ( - 3b ) when ( + ) ( - ) become ( - ) another ( - ) ( - ) = ( + ) ;; ( - ) ( + ) = ( - ) ; ; ( + ) ( + ) = ( + )
17a - 3b is the answer
