Firstly we will start by expanding the brackets. We will do 2a + 23 for the first bracket, then we will do 5a + 5(-1) for the second bracket which will give us 2a + 6 + 5a - 5. We will then simplify what we have. In order to collect terms and simplify, they must be of the same 'type' ie numbers on their own without letters can be collected and numbers that have been multiplied by a letter can be collected as long as they have the same letter. We can now collect the terms as such 2a + 5a + 6 - 5 This will then give us 7a + 1