Talia's gym membership costs $75 a month plus $30 additional for each month she brings a guest. Which equation shows the number of months Talia brings a guest if she spends $990 on a one year membership?

75 * 12 + 30m = 990

∴ m = 3

Step-by-step explanation:

Assume the number of months Talia brings a guest to be 'm'.

So the amount of Talia has to pay for guests for one year is $ 30m.

So, total amount of money Talia has pay for one year = (monthly membership cost) * (number of months in a year) + (additional amount for guests)

Total cost = $990

Monthly membership cost = $75

Number of months in a year = 12

Additional amount for guests = $ 30m

∴ The equation which gives you the number of moths she brought guests is:

990 = 75*12 + 30m

990 = 900 + 30m

990-900 = 30m

30m = 90

∴ m = 3