Mario was given some birthday money. he puts the money in an account. every month after that, he deposits the same amount of money. the equation that models this situation is y = 75x + 50, where y is the amount of money in the account and x is the number of deposits. what does the y-intercept mean in this situation? a. he puts $75 in the account each month. b. he puts $50 in the account each month. c. he was given $75 for his birthday. d. he was given $50 for his birthday.