Final answer:
The second equation in the system to find how many months it will take Jamie to pay off the balance is y = 275x + 300.
Step-by-step explanation:
To find the second equation in a system to determine how many months it will take for Jamie to pay off the balance, we need to consider her monthly payment of $275 and the extra amount she can afford to pay of $300. The equation for the monthly payment would be y = 275x, where y represents the remaining balance and x represents the number of months. To include the extra amount, we add it to the monthly payment, so the second equation in the system would be y = 275x + 300.