Jack's Plumbing charges customers $100 per hour for repair jobs. A-1 Plumbing charges according to the equation y=75x+50 , where x = time in hours and y = cost in dollars. Explain why A-1 Plumbing charges less than Jack's Plumbing for a 4‑hour repair job. Does A-1 Plumbing charge less than Jack's Plumbing for all repair jobs? Explain why or why not.