1.) Get the equation in the form y = ax^2 + bx + c.
2.) Calculate -b / 2a. This is the x-coordinate of the vertex.
3.) To find the y-coordinate of the vertex, simply plug the value of -b / 2a into the equation for x and solve for y. This is the y-coordinate of the vertex.
His 3-hour head start puts Mr. Cunningham 165 miles ahead of her. She makes that up at the rate of (75 -55) = 20 mph, so will overtake Mr. Cunningham after (165 mi)/(20 mi/h) = 8.25 hours.