Complete Question
The complete question is shown on the first uploaded image
Answer:
The point of diminishing returns (x , y ) is (11, 21462)
Step-by-step explanation:
From the question we are told that
The function is 
Here R(x) represents revenue (in thousands of dollars) and x represents the amount spent on advertising (in thousands of dollars).
Now differentiating R(x) we have

Finding the second derivative of R(x)

at inflection point 
So 
=> 
substituting value of x into R(x)


Now the point of diminishing returns (x , y ) i.e (x , R(x) ) is
(11, 21462)
<h2><u><em>
This would be the SSS theorem.</em></u></h2>
The reason would be because the diagram shows already that the two sides are congruent to the other two sides. The line in the middle is congruent to itself. (Reflexive Property) Because we now have three congruent sides, we can say that the SSS theorem proves the two triangles congruent