Rearrange, 5(a + b)= 2ab , to make 'a' the subject

The question is asking for 'a' to be the subject and therefore our aim is to result in an answer with the form 'a='. The first step is to expand the brackets on the left hand side by multiplying 'a' by 5 and then 'b' by 5 to result with 5a + 5b= 2ab. Now that we want to make 'a' the subject we need to reaarange the equation such that all the 'a' terms are on one side and the 'b' terms on the other. By minusing '5a' from both sides of the equation (as we have to do the same to both sides) we end up with the equation: 5b= 2ab - 5a. As there are two 'a' terms on the right hand side we are now able to factorise and do the opposite to what we did in the first step. By removing the common 'a' from both terms and introducing brackets we end up with 5b= a(2b-5). The final step to this question is to make 'a' the subject. By dividing both sides by '2b-5' we can move the '2b-5' to the left hand side and leave 'a' to be the subject. This will give us the final answer of a= 5b/ 2b-5. This question is most likely worth 3 or 4 marks and therefore inclusion of every step is key to ensure you gain all the marks!