Question

5a-[3b+7-(4a-5b)+(2-a)]

Answer 1

5a - [ 3b + 7 - ( 4a - 5b ) + ( 2 - a ) ] =
5a - [ 3b + 7 - 4a + 5b + 2 - a ] = 
5a - [ - 4a - a + 3b + 5b + 7 + 2 ] =
5a - [ - 5a + 8b + 9 ] =
5a + 5a - 8b - 9 =
10a - 8b - 9

Answer 2

5a-[3b+7-(4a-5b)+(2-a)]
5a - [3b + 7 -4a + 5b +2 -a]
5a - [3b + 5b - 4a - a + 7 + 2]
5a - [8b - 5a + 9]
5a - 8b + 5a - 9
10a - 8b - 9