Write an expression for the model. find the sum

Ahiker stands at an unknown elevation before he ascends 2 miles up a mountain to an elevation of 9 miles. find the elevation of the hiker before his ascent.

Ineed with math stuff it involves graphs

An object is accelerating at a constant rate. its velocity in feet per second as a function of time in seconds can be modeled by the linear function v(t) = 2.5t. what does the dependent variable represent for this function? a) acceleration b) distance c) slope d) velocity