What is the volume of a cube and 1/3 inch side

What is the y-intercept of the line given by the equation

You dug a hole that was 8 feet deep. after taking a short break, you dug down 3 more feet in the same hole. when finished digging, a tractor accidentally filled the hole with 4 feet of dirt. how deep is your hole now?

#7. m is the midpoint of pq, the diameter of the circle o is 13in. and rm = 4in. find pm find pq