One of the variables in our case study is City MPG, which is the number of miles a vehicle can travel in city conditions on one gallon of gas. Because we have information on the entire population of 1141 vehicles, we know the sample standard deviation 5.637 mpg. We obtained a sample of 100 vehicles and observed a sample mean city gas mileage of 20.71 mpg.

if the eqn of the parabola is f(x) = (x-4)(x+2), we need to mult. this out to find the coordinates of the vertex.

then f(x) = x^2 + 2x - 4x - 8, and f(x) = x^2 - 2x - 8.

one way in which you can find the vertex is to calculate x = -b / (2a).   here, that comes to

        )

x = = 1.   f(1) = 1^2 - 2(1) - 8 = - 9.   vertex is at (1, -9).

        2(1) 

find another point on the curve:   let x=0, for which y=-8.   then (0, -8) is on the curve.   plot the vertex and this point and draw a smooth parabola thru both.

hope this

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step-by-step explanation: