Question

So um anyone know how to do this?

Answer 1

We need to find distance they travel as a function of time. This simply means that x is the function of time. The destination is 120 miles away, this is irrelevant for the question that is currently being asked. However, we know that they have already travelled 20 miles and are going 50 miles and hour. So lets plug in what we have.

50 is our rate of change, so we match that with the x.

20 is our constant, the distance already travelled.

This means our function is:

f(x) = 50x + 20

This means our answer is D) f(x) = 50x + 20

Lets also plug in 120 to solve how much further they need to travel before arriving.

120 is our f(x) as it is the final distance travelled.

120 = 50x + 20

120-20 = 50x

100 = 50x

100/50 = x

2 = x

This means that they need to travel 2 hours in addition to the 20 miles they have already gone.

I hope I've helped! :)