Answer:

Explanation:
To complete the square you need to add
to both sides. (Parenthesis around b/2)
b = 10
b/2 = 5
(b/2)^2 = 25
+10x + 16 = 0
subtract 16 to both sides
+ 10x = -16
add 25 to both sides
+10x + 25 = 9
Perfect Square Trinomial Factoring
= 9