a) You are told the function is quadratic, so you can write cost (c) in terms of speed (s) as
... c = k·s² + m·s + n
Filling in the given values gives three equations in k, m, and n.

Subtracting each equation from the one after gives

Subtracting the first of these equations from the second gives

Using the next previous equation, we can find m.

Then from the first equation
[tex]28=100\cdot 0.01+10\cdot (-1)+n\\\\n=37[tex]
There are a variety of other ways the equation can be found or the system of equations solved. Any way you do it, you should end with
... c = 0.01s² - s + 37
b) At 150 kph, the cost is predicted to be
... c = 0.01·150² -150 +37 = 112 . . . cents/km
c) The graph shows you need to maintain speed between 40 and 60 kph to keep cost at or below 13 cents/km.
d) The graph has a minimum at 12 cents per km. This model predicts it is not possible to spend only 10 cents per km.
Answer:
A and C
Step-by-step explanation:
B has a solution and D is 0. A and C are the only ones with no solution.
Answer:
Width = 
Step-by-step explanation:
All we have to do is to use the method of changing the subject. First we know that length * width is equal to area.
Area = length * width
We have the area and the length but we don't have the width. So we substitute the values we have int the equation and make the width (w) the subject.
(c^2 - 4x - 12) = (x + 2) * w
(c^2 - 4x - 12) = w(x +2)
Divide both sides by (x+2) so w can stand alone.

w = 
Answer:
1, 4 2, -3 3, 5.5 4, -2.5
Step-by-step explanation:
180 cm. it is that answer because ...
K H D U D C M
71 m times 100 is 180