How do i do this? what’s the answer?

F(x) = 5x

for f(7) you replace x with 7 so it will be : f(7) = 5(7) = 35

Well in order to lose a pound you would have to burn 1,500 calories. the more calories you burn the more weight you lose. in order to lose 2 pounds you would have to run 4 hours and 28 minutes.