Answer:it costs $1150 to rent the apartment for one month.
Step-by-step explanation:
Let x represent the cost to rent the apartment for one month.
They must pay the landlord two months' rent and $500 security deposit when they sign the lease. This means that the security deposit is constant and independent of the number of months that they want to pay for.
The total amount they pay the landlord is $2800. Therefore
2x + 500 = 2800
2x = 2800 - 500 = 2300
x = 2300/2 = 1150