How to factorise 24x+3

The first thing to do is to work out the biggest number that goes into bother 24 and 3. As the only that goes into three - other than 1 - is itself, one can assume this is the number we are looking for.

Next, divide bother numbers by 3.

24 / 3 = 8

3 / 3 = 1

You now take 3 out of the brackets, and leave 8 and 1. 24x / 3 = 8x.

3 (8x + 1)