9x^2-16y^2=
(3x+4y)(3x-4y)
Answer:



Step-by-step explanation:
r = Radius
h = Height
Volume of cylinder = 

Surface area is given by

Differentiating with respect to radius we get

Equating with zero we get


So, the value of the function is minimum at 

So, the radius and height which would minimize the surface area is 1.05 feet and 2.12 feet respectively.
Surface area

The minimum surface area is
.
The total number of days taken to make the batch of pens is 22.
<h3>What is Linear Expression?</h3>
An equation that has the highest degree of 1 is known as a linear equation. This means that no variable in a linear equation has an exponent more than 1.
Based on the given conditions, formulate: 8 + 20 - 8 X 9 ÷ 12
Calculate the product or quotient: 8 + 20 - 72/12
Cross out the common factor: 8 + 20 - 6
Calculate the sum or difference: 28 - 6
Calculate the sum or difference: 22
Thus, the total number of days taken to make the batch of pens is 22.
Learn more about Linear Expression from:
brainly.com/question/819568
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Answer:
I believe the answer to this question is: In Picture.