Joy baked 2 pizzas and cut each pizza into 8 slices. Joy and her brother ate all but 4 slices of the pizza. Which equation can be used to find s, the number of slices joy and her brother ate?

2 x s = 8 x 4

2 x 8 + 4 = s

s = (2 + 8) - 4

8 x 2 = s + 4