Explanation:
We'll use the distributive rule in reverse
5x+35 = 5*x + 5*7 = 5(x+7)
In general, the distributive rule is a*(b+c) = a*b+a*c. We multiply the outer term 'a' by each term inside the parenthesis.
When going from 5(x+7) to 5x+35, we multiply the outer 5 by each of the terms inside.