Kelly joins powerhouse gym. the cost is $30 per month and a one-time $100 joining fee. lisa joins megamuscle gym for $35 per month and a $50 joining fee. in how many months will lisa have paid more than kelly?

Start by making a formula for the price of each gym:
Powerhouse has a $100 entry fee, the constant, leaving $35 to go with your variable. Lets say m, which gives you the equation:
100 + 30m
Repeat the same thing for Megamuscle gym and you have the equation:
50 + 35m
Insert numbers for m (number of months) from 1 - 12 until you get a number for Lisa that is larger than Kelly's, which would be 11 months.
Kelly would have paid $430, with Lisa paying $435 in 11 months.

b

step-by-step explanation:

a difference is the result of subtraction. while each of these expressions has subtraction in it, a difference will be the result when subtraction is the last operation applied in the order of operations for the expression. this means subtraction must be outside of the parenthesis. only b has this.