The graph of a function must be linear if it has what characteristic? It passes through the origin.
It crosses the x-axis more than once.
It crosses the y-axis exactly once
It has a constant slope

Johnny rode his bike to a friends house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was unable to play. what was his displacement for the total bike ride trip? what could you use as a reference point ? show the steps to solve this problem.