Answer:
312a + 102b - 468
Step-by-step explanation:
1) First solve the parenthesis.
9 [ 7(3a + 2b - 4) + 12(a - 2) ] + 3(5a - 8b)
9 [ 21a + 14b - 28 + 12a - 24) ] + 15a - 24b
2) Combine like terms.
9 [ 33a + 14b - 52) ] + 15a - 24b
3) Solve the bracket.
297a + 126b - 468 + 15a - 24b
4) Combine like terms.
312a + 102b - 468
