Expand and simplify the following equation 5a(4b - 3) - 2a(6 + b)

In order to simplify this equation, first we need to expand the two brackets.
To expand 5a(4b - 3) we multiply 5a with each term inside the brackets. Therefore, we get 5a * 4b - 5a * 3 = 20ab - 15a
Doing the same thing for 2a(6 + b), we get 12a + 2ab
Now to simplify the equation we put together the two new terms:
20ab - 15a - (12a + 2ab) = 20ab - 15a - 12a - 2ab
Grouping up the first and the last term, we get the final expression: 
18ab - 27a