Question

Talk the Talk Cellular charges a base rate of $20 per month for unlimited

texts plus $0.15/minute of talk time. The monthly cost for x minutes is
given by f(x) = 20 + 0.15x.

Answer 1

Yes, that equation you gave is the correct equation to model this situation. Did you want us to check that your answer was correct? Or did you accidentally leave out the final part of the question?