Answer:
<h3>1 secs</h3>
Step-by-step explanation:
Given the height of the discus can be modeled by the equation y=−16x
^2
+32x+4, where y represents the height in feet of the discus in seconds, the velocity of the discus at its maximum height is zero.
Velocity v = dy/dx = 0
dy/dx = -32x + 32
0 = -32x + 32
32x = 32
x = 1 secs
Hence it will take the discus 1 secs to reach its maximum height
Answer:
Volume = 35185.8 
Step-by-step explanation:
Recall the formula for the volume of a cone: 
Where R is the radius of the cone's circular base (in your case half of 80 km,(that is 40 km)
And h stands for the height of the cone (in your case 21 km)
We replace such in the formula and calculate its final value:

We round it to the number of decimals your problem request (let's say to one decimal) and also include the cubic units:
Volume = 35185.8 
Answer: 32 kilograms
Step-by-step explanation:
Cross multiply and divide.
20/5
x/8
The answer should be 32.
All you have to do to solve this question is to plug in gx as any other number you would plug in to the f(x) to solve the equation.
So it would be
F(3x-8) = 3(3x-8)^2 - 5(3x-8) - 9
Then FOIL the terms in the binomial or the first term, then after expanding the first term, distribute the numbers into each term inside the bracket and then at the end gather like terms to simplify.