Vaquera Enterprises, Ltd., opened up a savings account to store the profit from a lucrative
food distribution business. The amount of money in the account is modeled by the function
f (x)= 5x² +65x, where 'x' represents the number of months that Vaquera Enterprises
has had the account, and f (x) represents the money in the account. After how many
months will the profits reach $700?
A. 5
B. 65
C. 20
D. 7