A water park charges $5 for entry into the park and an additional $2 for each of the big water slides. Steven spent $17 on his visit to the water park. Which equation can be used to find the number of big water slides, x, that Steven went on?

5 + 2x = 17
5x + 2 = 17
5x + 2x = 17
5 + 2 = 17x