how do i solve this problem i dont understand how to do it
You're being asked to factor this polynomial b2 + 8b + 7 into two factors (binomials). If you "FOIL" or redistribute the two binomials, you should obtain the original polynomial.
With this idea, what are the factors of b2? Just b*b. So the first terms of your factors will be:
(b + )(b + )
You notice I filled in the +'s because the original problem had two +'s.
Now what are the factors of 7? Just 7*1, so now we fill that in and we are done!
(b + 7)(b + 1)