   SEARCH HOME Math Central Quandaries & Queries  Question from Salem, a student: A fitness center offers a special price for group-class students. The cost of registration is 30 dollars and then you have to pay 25 dollars per month. What is the rule of the equation in the light of c=---m+----? Hi Salem,

In this example you are joining the fitness center for a number of months and you want to know what it will cost. When writing an algebraic equation you need to say what the letters represent. Let $m$ be the number of months you plan to belong to the fitness center and $c$ is the cost of this membership in dollars.

If you only join for 1 month ($m = 1$) then the cost will be $\$25 + \$30 = \$55.$If you join for 2 months ($m = 2$) you will need to pay the$\$25$ fee twice and the registration fee once so the cost will be $2 \times \$25 + \$30 = \$80$. If you join for 3 months you will need to pay the$\$25$ fee three times and the registration fee once. What is the value of $m?$ What will the cost be?

If you join for 6 months you will need to pay the $\$25$fee six times and the registration fee once. What is the value of$m?$What will the cost be? If you join for$m$months you will need to pay the$\$25$ fee $m$ times and the registration fee once. What will the cost be?

This is the expression you are looking for.

Write back if you need more assistance,
Penny      Math Central is supported by the University of Regina and the Imperial Oil Foundation.