Given, y varies directly as x
So,
Where c is a constant
When y equals 5 when x is 8
So,
So, the relation between y and x
now , when x = 9
Substitute with x to find y
So, the answer is option 2. y = 45/8
Find the equation of the line with a slope of -2 that passes through the point (4,-3)
1 answer:
You might be interested in
Answer:
a) h = 123/x^2
b) S = x^2 +492/x
c) x ≈ 6.27
d) S'' = 6; area is a minimum (Y)
e) Amin ≈ 117.78 m²
Step-by-step explanation:
a) The volume is given by ...
V = Bh
where B is the area of the base, x^2, and h is the height. Filling in the given volume, and solving for the height, we get:
123 = x^2·h
h = 123/x^2
__
b) The surface area is the sum of the area of the base (x^2) and the lateral area, which is the product of the height and the perimeter of the base.
__
c) The derivative of the area with respect to x is ...
When this is zero, area is at an extreme.
__
d) The second derivative is ...
This is positive, so the value of x found represents a minimum of the area function.
__
e) The minimum area is ...
The minimum area of metal used is about 117.78 m².
