For this case we have the following equation:
x2 + 4x = 14
By completing squares we have:
x2 + 4x + (4/2) ^ 2 = 14 + (4/2) ^ 2
Rewriting we have:
x2 + 4x + (2) ^ 2 = 14 + (2) ^ 2
x2 + 4x + 4 = 14 + 4
x2 + 4x + 4 = 18
(x + 2) ^ 2 = 18
Answer:
A. (x + 2) 2 = 18
