Answer:
(1) 4 (2) -2
Step-by-step explanation:
{\text{Direction of parabola depends on the sign of quadratic coefficient of a }} \hfill \\
{\text{quadratic equation}}. \hfill \\
{\text{For given quadratic equation}}. \hfill \\
a{x^2} + bx + c = 0 \hfill \\
{\text{The parabola is in the upward direction if }}a{\text{ }} > {\text{ }}0{\text{ and in downward direction if }}a < 0 \hfill \\
{\text{Here, the equation of given parabola is }} \hfill \\
{x^2} - 6x + 8 = y \hfill \\
\Rightarrow y = \left( {{x^2} - 6x + 9} \right) - 9 + 8 \hfill \\
\Rightarrow y = {\left( {x - 3} \right)^2} - 1. \hfill \\
{\text{Thus, the parabola is in the upward direction}} \hfill \\
At the first place is better because
$0.8 * 5 = $ 4
$4.5 / 5 = $0.9
Is more expensive in the another place
7.5
The relation between time, speed, and distance is ...
time = distance/speed
If distance is "1 round trip", then the time going is ...
going = 0.5/(10 mi/h) . . . . for 1/2 round trip
and the time coming is ...
coming = 0.5/(6 mi/h)
Then the average speed for the full round trip is ...
speed = distance/time
average speed = 1/(going + coming) = 1/(0.5/10 +0.5/6) mi/h
= 1/((3+5)/60) mi/h
= 60/8 mi/h = 7.5 mi/h
Jack's average speed for the round trip was 7.5 mph.
66
