What is equivalent to -15 - 12

What is the y intercept of f(x)=(1/2)^x?

What’s the range cuz i can’t find it?

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.