The position function of a particle is given by:

The velocity function is the derivative of the position:

The particle will be at rest when the velocity is 0, thus we solve the equation:

The coefficients of this equation are: a = 2, b = -9, c = -18
Solve by using the formula:
![t=\frac{-b\pm\sqrt[]{b^2-4ac}}{2a}](https://tex.z-dn.net/?f=t%3D%5Cfrac%7B-b%5Cpm%5Csqrt%5B%5D%7Bb%5E2-4ac%7D%7D%7B2a%7D)
Substituting:
![\begin{gathered} t=\frac{9\pm\sqrt[]{81-4(2)(-18)}}{2(2)} \\ t=\frac{9\pm\sqrt[]{81+144}}{4} \\ t=\frac{9\pm\sqrt[]{225}}{4} \\ t=\frac{9\pm15}{4} \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20t%3D%5Cfrac%7B9%5Cpm%5Csqrt%5B%5D%7B81-4%282%29%28-18%29%7D%7D%7B2%282%29%7D%20%5C%5C%20t%3D%5Cfrac%7B9%5Cpm%5Csqrt%5B%5D%7B81%2B144%7D%7D%7B4%7D%20%5C%5C%20t%3D%5Cfrac%7B9%5Cpm%5Csqrt%5B%5D%7B225%7D%7D%7B4%7D%20%5C%5C%20t%3D%5Cfrac%7B9%5Cpm15%7D%7B4%7D%20%5Cend%7Bgathered%7D)
We have two possible answers:

We only accept the positive answer because the time cannot be negative.
Now calculate the position for t = 6:
Answer:
60 ; 5220
Step-by-step explanation:
A) From the horizontal bar chart provided, it could be inferred that 85 people spell the word 'weird' correctly. The graph is scaled on a fixed interval of 10. Hence, the midpoint of 10 = 5
(80 + 5) = 85
B) In a group consisting of 8719 randomly selected people estimate how many more people can correctly spell weird than inoculate
From the graph :
85 per 100 could spell weird correctly while,
About 25 per 100 could spell inoculate correctly.
Difference In number per 100 people
(85 - 25) = 60 people per 100
We could round 8719 to the nearest 100 = 8700
Number of 100's in 8700 = 8700/100 = 87
(87 × 60) = 5,220 people