The goal here is to isolate a. To do this, first you must multiply both side of the equation by 13. This will cancel out the denominator on the left side of the equation, giving you: -3 * 13 = -a/13 * 13. Simplified, this becomes: -39 = -a
The only thing still attached to the a is a negative one. Now you divide both sides by negative one, giving you: -39/-1 = -a/-1 or 39=a
That's your answer: a =39
Hope this helps!
