b^2 + 10b +25
(b+5) (b+5)
The reason is FOILing
First, multiply the two first numbers of each binomial
(b*b) = b^2
Next, multiply the outer numbers/terms
(b*5) = 5b
Then, multiply the outer terms:
(5*b) = 5b
Finally, multiply the last terms
(5*5) = 25
Then, put it all together
b^2 + 5b + 5b +25
Simplify (add like terms)...
b^2 + 10b + 25
Therefore, your answer is:
b^2 + 10b + 25 = (b+5) (b+5)
