Which exponential function has an x-intercept a) f(x)=100^x-5 -1 b) f(x)=3^x-4 -2 c) f(x)=7^x-1 +1 d) f(x)=8^x+1 -3

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?