The first few steps in solving the quadratic equation 8x2 + 80x = −5 by completing the square are shown. 8x2 + 80x = −5 8(x2 + 10x) = −5 8(x2 + 10x + 25) = −5 + which number is missing in the last step? −200 −25 25 200

Completing the square is done as follows:

1. Write the equation in a way that the constants are in the right side while the terms with x are on the left. 
8x^2 + 80x = −5

2. Make sure that the coefficient of the x^2 term is 1.
8(x^2 + 10x) = -5

3. Adding a term to both sides that will complete the square in the left side. This is done by dividing the coefficient of the x term by 2 and squaring it. Note: The same amount should be added to the right side to balance the equation.
8(x2 + 10x + 25) =-5 +200

8(x+5)^2 = 195