Help please! It's a quiz. will mark brainliest for correct answer!

A cell phone company charges $45 per month for unlimited calls
and $0.25 per text message. Another cell phone company
charges $0.15 per text message and $70 per month for unlimited
calls.
a. Write and solve an equation to represent the
number of text messages sent in a month that
would make each plan cost the same amount.
b. How many months would that be? What would the
cost be?