A student was given the equation x^2 + 6x - 13 = 0 to solve by completing the square. The first

step that was written is shown below.

x^2 + 6x = 13

The next step in the student’s process was x^2 + 6x + c = 13 + c.

State the value of c that creates a perfect square trinomial.

Explain how the value of c is determined.