Write a direct variation equation that relates r and y. Then find the value of y when r equals the value indicated

Which of the following graphs could represent a cubic function?

Which of the following is best modeled using a linear equation y=ax+b, where a is less than 0?

If two parallel lines are cut by a transversal, interior angles on the same side of the transversal are supplementary. a. always b. sometimes c. never