An automobile's velocity, starting from a complete stop, is v(t) =140/5t - 6 where v is measured in feet per second. After what elapsed time would the automobile reach a
velocity of 44 feet per second?

- both graphs increase on their domain.

- the graphs of both functions have the same x-intercept.

- neither graph has a y-intercept.

sample answer: you can determine whether each element of the domain is paired with exactly one element of the range. for example, if given a graph, you could use the vertical line test; if a vertical line intersects the graph more than once, then the relation that the graph represents is not a function.