Answer:
7(5c+2b-1)
Explanation:
GCF stands for greatest common factor, so you need to find a common factor between 35, 14, and -7. Use a method of your choice to find the GCF and you should find that it's 7. Then, you take the 7 "out" and put parentheses around the original equation while dividing every "term" by 7.