You can put this solution on YOUR website!
This is the way you complete the square.
The rules is divide the coefficient of x by 2, then square that value
That give you the 3rd term in a perfect square:
x^2 + 8x + ____
In this problem the coefficient of x is 8
Divide by 2, results in 4
Square 4; results is 16
x^2 + 8x + 16
If you factor
(x+4)(x+4); FOIL this and you get the equation above, right?