Marty’s dog can run 3 miles in 20 minutes. What is the dog’s speed in miles per hour? How do you get the answer. Can you please simplify the answer so I can understand, please

Heather is writing a quadratic function that represents a parabola that touches but does not cross the x-axis at x = -6. which function could heather be writing? fx) = x2 + 36x + 12 = x2 - 36x - 12 f(x) = -x + 12x + 36 f(x) = -x? - 12x - 36