Katie solved the equation by completing the square.

x^2+12x-7=0

Which equation shows one of the steps Katie could have taken to complete the square?

x^2+12x+144=7

x^2+12x+144=7+144

x^2+12x+36=7+36

x^2+12x+36=7

The correct answer is C. x^2+12x+36=7+36

This is because the first two steps of completing the square are the following.

1. Add/subtract the constant, to the right side. You can see this by adding the 7 to the right side of the equation.

2. Take half of the coefficient of x (12) and square it. Half of 12 is 6. 6 squared is equal to 36. Now you add that to both sides.

With these being the first two steps, answer C is the only one that represents those appropriately.