let y be the total cost for going to gymx be the number of months they go to gym
Gym rats health club has a starting membership fee of $25 and charges $12 per month.
y = 12x + 25
greens and soy health club has a starting membership fee of $35 and charges $10 per month.
y = 10x + 35
equate the two equation
12x + 25 = 10x + 3512x - 10x = 35 - 252x = 10x = 10/2x = 5 months
y = 10(5) + 35y = $ 85