Isolate the a. Note the equal sign. What you do to one side, you do to the other.
Add 5 to both sides
-5 (+5) + 1/5a = 4 (+5)
1/5a = 9
Isolate the a. Multiply 5 to both sides
(5)(1/5)a = 9(5)
a = 9 x 5
a = 45
45 is your answer for a.
hope this helps
