Hello from MrBillDoesMath!
Answer:
Choice A, 1/4
Discussion:
Consider the perfect square
(x + a)^2 = x^2 + (2a)x + a^2
The constant term (a^2) equals 1/2 the coefficient of x (i.e. 2a), squared.
Let's apply this idea to x^2 + x
x^2 + x = => as 2 * 1/2 = 1
x^2 + ( 2 * 1/2)x =
( x^2 + (2* 1/2)x + ( 1/2) ^2 ) - (1/2) ^2 =
as constant term to add is 1/2 coefficient of x (that is, 1/2) and
(1/2)^2 - (1/2)^2 = 0
(x + 1/2) ^ 2 - (1/2)^2
In other words add the constant (1/2)^2 = 1/4, which is Choice A.
Thank you,
MrB
