Step 1. Rearrange the order of terms so we can start grouping
Step 2. Now factor out 7a from the first group and 2c from the second group.
Step 3. We see that (a-b) is a common factor in the two groups, so factor it out...
Step 4. ANSWER:
I hope the above steps were helpful.
For FREE Step-By-Step videos in Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra and for Trigonometry visit http://www.FreedomUniversity.TV/courses/Trigonometry.