Answer: 7x + 12
Step-by-step explanation:
The price of each plan = $x
Since three of the seven friends pay an extra $4 per month for unlimited text messaging, the cost of the three friends will be:
= 3(x + 4)
The cost if the other four friends will be:
= 4 × x
= 4x
Therefore, the total cost of the seven plans will be:
= 4x + 3(x + 4)
= 4x + 3x + 12
= 7x + 12
