Final answer:
To solve the equation x^2 - 8x = -10 by completing the square, you need to add a value to both sides of the equation to make the left side a perfect square trinomial. In this case, the value that needs to be added is 16. So the correct answer is (C) 16.
Step-by-step explanation:
To solve the equation x2 - 8x = -10 by completing the square, we need to add a value to both sides of the equation to make the left side a perfect square trinomial.
In order to do this, we take half of the coefficient of the x term, square it, and add it to both sides of the equation.
In this case, the coefficient of the x term is -8, so half of that is -4. We square -4 to get 16. Therefore, the value that needs to be added to both sides of the equation is 16. So the correct answer is (C) 16.