Rearrange the following making a the subject: (a+2)/5 = 3a+b

(a+2)/5 = 3a+b  ...first, we need to multiply both sides by 5

a + 2 = 5 (3a + b)  ....to be able substract 3a from the right side we need to remove the bracket. We multiply the bracket by 5.

a + 2 = 15a + 5b  ...now we need to make sure all element containing a are on the same side of the equation. We do -a and -5b

a + 2 -a -5b = 15a + 5b - a - 5b ...to make it easier to imagine, we can write the equation like this

2 - 5b = 14a  ...Finally, we need to make 1a the subject so we devide the equation by 14

(2-5b) / 14 = a  ...Congratulations!!!