Sarah exercised for 30 minutes. Kari exercised long enough to burn 800 Calories. Who exercised for a longer
period of time, Sarah or Kari? Explain

Karl exercised longer - it takes the average person several hours to burn 800 calories, or an hour at least. If he really tried, he could feasibly do it in 40 minutes, but likely not less. This is an educated guess because the question doesn't give enough information.

Step-by-step explanation:

Knowledge about the human body and how quickly we burn calories.

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