The function f(x)=30x+150 represents the total cost of a gym membership at Jon’s Gym for x months plus a signup fee. Bella’s Gym has a signup fee of $50 and charges $45 dollars per month. Which statement is true?

1. The monthly charge at Bella's gym is $15 less than the monthly charge at Jon's gym.

2. The monthly charge at Bella's gym is $15 more than the monthly charge at Jon's gym.

3. The monthly charge at Bella's gym is $5 less than the monthly charge at Jon's gym.

4. The monthly charge at Bella's gym is $5 more than the monthly charge at Jon's gym.