Please help it’s difficult

Another type of subtraction equation is 16-b=7. explain how you would sole this equation then solve it.

Solve the problem by making up an equation. a man could arrive on time for an appointment if he drove the car at 40 mph; however, since he left the house 15 minutes late, he drove the car at 50 mph and arrive 3 minutes early for the appointment. how far from his house was his appointment?

If f(x) = 4x - 3 and g(x) = x + 4, find (f - g) (x)