Step 2. Goal is to have variable terms on one side and numbers on the other side. Let's add 8a to both sides of equation. This gets rid of a terms on the right side.
Step 3. Subtract 17 from both sides of equation. This gets of rid of number terms on left side to obtain a terms only.
Step 4. Divide 13 from both sides of equation to solve for a.
Step 5. Answer is a=-3
Hope the steps were helpful. Good luck in your studies.
Respectfully,
Dr J
For Step-By-Step videso on Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra.