Since x represents the year, year 15 will be 15 years.
Plug in "15" as your "x"
y = -2(15)^2 + 36(15) + 6
15^2 = 225 (Exponents come before multiplication)
y = -2(225) + 36(15) + 6
y = -450 + 540 + 6
y = 90 + 6
y = 96
<em>The answer is B</em>
A quadratic equation is in the form of ax²+bx+c. The time at which the height of the ball is 16 feets is 0.717 seconds and 1.221 seconds.
<h3>What is a quadratic equation?</h3>
A quadratic equation is an equation whose leading coefficient is of second degree also the equation has only one unknown while it has 3 unknown numbers. It is written in the form of ax²+bx+c.
The complete question is:
A ball is thrown from an initial height of 2 feet with an initial upward velocity of 31 ft/s. The ball's height h (in feet) after 7 seconds is given by the following, h=2+31t-16t². Find all values of t for which the ball's height is 16 feet. Round your answer(s) to the nearest hundredth.
The time at which the height of the ball is 16 feet can be found by,
h = 2 + 31t - 16t²
16 = 2 + 31t - 16t²
16 - 2 - 31t + 16t² = 0
16t² - 31t + 14 = 0

t = 0.717 , 1.221
Hence, the time at which the height of the ball is 16 feets is 0.717 seconds and 1.221 seconds.
Learn more about Quadratic Equations:
brainly.com/question/2263981
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Answer:
x= 5
?=10
Step-by-step explanation:
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The mass of sodium chloride required for 1. 8 × 10^3 people is 3. 6 × 10^5 grams. Option A is the correct answer.
<h3>
How do you calculate the mass of sodium chloride required?</h3>
Given that weigh of the person is 50 KG. The mass of the sodium chloride in one person is given below.

The mass of sodium chloride is calculated as given below.


Hence we can conclude that the mass of sodium chloride required for 1. 8 × 10^3 people is 3. 6 × 10^5 grams. Option A is the correct answer.
To know more about the mass, follow the link given below.
brainly.com/question/15959704.