Using the mean concept, it is found that the value of the number that was removed was of 4.
<h3>What is the mean?</h3>
The mean of a data-set is given by the <u>sum of all observations in the data-set divided by the number of observations</u>.
The mean of five numbers is 8, hence, the sum of the numbers is given by:
S = 5 x 8 = 40.
If one of the five numbers is removed, the mean becomes 9, hence, the sum of the four numbers is given by:
S = 4 x 9 = 36.
The difference is:
40 - 36 = 4.
Hence, the value of the number that was removed was of 4.
More can be learned about the mean concept at brainly.com/question/25122507
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Answer:
f(3) = 3
Step-by-step explanation:
f(1) = 1
f(2) = 2
f(n) = f(n − 2) + f(n − 1)
f(3) = f(3 - 2) + f(3 - 1)
= f(1) + f(2) = 1 + 2 = 3
Special Note: Have you heard of the Fibonacci sequence?
The formula f(n) = f(n − 2) + f(n − 1) is used to find the terms of the of the Fibonacci sequence
<u>ANSWER TO PART A</u>
The given triangle has vertices 
The mapping for rotation through
counterclockwise has the mapping

Therefore



We plot all this point and connect them with straight lines.
ANSWER TO PART B
For a reflection across the y-axis we negate the x coordinates.
The mapping is

Therefore



We plot all this point and connect them with straight lines.
See graph in attachment