Answer:
16
Step-by-step explanation:
A perfect trinomial is a trinomial which follows the format (x+a)^2,
an example would be x^2 + 6x + 9 which factors into (x+3)^2. The pattern to observe here is that the coefficient to the x term (6 in previous example) is always equal to the square root of the integer (9) multipled by 2.
In your question we have the coefficient to x be 8
Now to we have to work backwards to figure out what our number is, we can do this by dividing 8 by 2 -> 4, and squaring this number -> 16
Our number is 16
x^2 + 8x + 16
this factors out to (x+4)^2
