Write a function rule for the given situation:

Suppose you buy a gym membership with a [tex]$100 signing fee plus $[/tex]30 a month.

Use [tex]\( x \)[/tex] for the number of months and [tex]\( y \)[/tex] for the total cost.

Now, find how much money you've spent after 2 years.



Answer :

Let's break down the problem step by step.

1. Identify the Variables:
- Let [tex]\( x \)[/tex] represent the number of months for which the membership is held.
- Let [tex]\( y \)[/tex] represent the total cost of the membership after [tex]\( x \)[/tex] months.

2. Define the Costs:
- The signing fee is a one-time cost of [tex]$100. - The monthly fee is $[/tex]30 per month.

3. Formulate the Function Rule:
To calculate the total cost [tex]\( y \)[/tex] for [tex]\( x \)[/tex] months, we need to add the initial signing fee to the total cost of [tex]\( x \)[/tex] months of membership fees.

So, the function rule is:
[tex]\[ y = 100 + 30x \][/tex]

4. Calculate the Total Cost After 2 Years:
- There are 12 months in a year.
- After 2 years, the total number of months ( [tex]\( x \)[/tex] ) is [tex]\( 2 \times 12 = 24 \)[/tex] months.

Using our function rule [tex]\( y = 100 + 30x \)[/tex], we substitute [tex]\( x = 24 \)[/tex]:

[tex]\[ y = 100 + 30 \times 24 \][/tex]
[tex]\[ y = 100 + 720 \][/tex]
[tex]\[ y = 820 \][/tex]

Therefore, after 2 years, you've spent a total of $820 on the gym membership.