Part A: A highway's path can be found using the equation 2x - 3y = 21. Use the graphs of the functions to determine the number of intersections there will be between the railroad and the highway, and explain completely. Part B: A turnpike's route is determined by the equation y=1/3x^2

Prove algebraically how many intersections there will be between the railroad and the turnpike, showing all necessary work.