How do you factor b^2+8b+7

Question

I need the answer to a algebraic expression 

Answer 1

Since the coefficient on b² is one, the coefficient on the b terms will be 1.

(b  ?)(b ?)

Since 7 can only be factored as 1 X 7, the last terms have be 1 and 7.  This works because the sum of

1X7 + 1X1 = 7 + 1 = 8

(b ? 7)(b ? 1)

Because the sign on the last term is positive, we know that the factors will have the same sign in them.  Since the sign on the second term is positive, we know that they will both be pluses.

(b + 7)(b + 1)