7 friends have a similar cell phone plans. The price of each plan is $x. This means that the basic cost of all the plans is $x. The total basic cost for the 7 plans would be
7 × x = $7x
3 of 7 friends pay an extra $4 per month for unlimited text messaging. The total amount paid by the 3 friends would be
3 × 4 = $12
Therefore, the total cost for the 7 plans would be
