You plot the point of the focus and the directrix on the graph to determine where the parabola opens.
We are provided the general forms of parabola according to its opening if:
it opens upward: (x - h)<span>² = 4a(y - k)
</span>it opens downward: (x - h)<span>² = -4a(y - k)
where "h" and "k" are the coordinates of the vertex, and "a" is the focal length from the focus to the vertex.
As you plot, the directrix y = 9 is a horizontal line, and the focus at (0,-9) is below that directrix. So, it means that the parabola opens downward (and not upward because the parabola must not touch to the directrix).</span> Next, identity the vertex (h,k). Note that the vertex is the midpoint between the focus and the point of the directrix. So the vertex is (0,0). Then, the focal length "a" is 9.
Hence, the equation is
(x - 0)<span>² = -4(9)(y - 0)
x</span><span>² = -36y</span>
3 2/5 = 17 / 5 ;
(17/5) ÷ (7/8) = (17/5) × (8/7) = 136/35 = 3.88 miles per hour ;
English translation:
If the quality control manager wants to estimate the average life of lamps with 20 hours, with a confidence level of 95% and an error of 10% is assumed. What is the sample size?
Answer:
They could sell 10 people one seat and 2 snacks each.
$24+$6+$6=$36
That's be $36x10=$360
Step-by-step explanation:
Answer:

Step-by-step explanation:
add the distribution property, then add 30 then - 14x then divide by 11