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The first four terms of a sequence are shown below.


8, 5, 2, -1


Which of the following functions best defines this sequence?


f(1) = 8, f(n + 1) = f(n) + 3; for n _ 1


f(1) = 8, f(n + 1) = f(n) - 5; for n _ 1


f(1) = 8, f(n + 1) = f(n) + 5; for n _ 1


f(1) = 8, f(n + 1) = f(n) - 3; for n _ 1


Which of the following statements best describes the effect of replacing the graph of y = f(x) with the graph of y = f(x) + 20?


The graph of y = f(x) will shift left 20 units.


The graph of y = f(x) will shift down 20 units.


The graph of y = f(x) will shift up 20 units.


The graph of y = f(x) will shift right 20 units.



Every week Annie plants 2 saplings in her garden. The function below shows the total number of saplings f(w) in her garden after w weeks.


f(w) = 2w + 3


Which statement best describes the y-intercept of the graph of the function?


It is equal to 3 and represents the original number of saplings in Annie's garden.


It is equal to 2 and represents the original number of saplings in Annie's garden.


It is equal to 3 and represents the number of saplings in Annie's garden at the end of the first week.


It is equal to 5 and represents the number of saplings in Annie's garden at the end of the first week.

Verified Answer :

1.) f(1) = 8, f(n + 1) = f(n) - 3; for n ≥ 1

2.) The graph of y = f(x) will shift up 20 units.

3.) It is equal to 3 and represents the original number of saplings in Annie's garden.

Part 1) The first four terms of a sequence are shown below.

Let

\(f(1)=8\\ f(2)=5\\ f(3)=2\\ f(4)=-1\)

we know that

\(f(2)-f(1)=5-8\\ f(2)-f(1)=-3\\ f(2)=f(1)-3\)

\(f(3)-f(2)=2-5\\ f(3)-f(2)=-3\\ f(3)=f(2)-3\)

\(f(4)-f(3)=-1-2\\ f(4)-f(3)=-3\\ f(4)=f(3)-3\)

So

\(f(n+1)=f(n)-3\)

therefore

the answer part 1) is the option

\(f(1) = 8, f(n + 1) = f(n) - 3; for. n\geq 1\)

Part 2) Which of the following statements best describes the effect of replacing the graph of y = f(x) with the graph of y = f(x) + 20?

Let

(a,b)--------->represent a point in the graph of f(x)

we know that

In the new function f(x)+d

(a,b)-----------> become-------> (a,b+d)

So

The new function f(x)+d shift up by d

therefore

in the new function \(f(x)+20\)-------> the graph of f(x) shift up by \(20\)

the answer part 2) is the option

The graph of y = f(x) will shift up \(20\) units.

Part 3) Every week Annie plants 2 saplings in her garden. The function below shows the total number of saplings f(w) in her garden after w weeks.

\(f(w) = 2w + 3\)

we know that

The y-intercept is when the value of w is equal to zero

the value of f(w) for

\(w=0\)

represent the original number of saplings in Annie's garden

so

For

\(w=0\\ f(0)=2*0+3\\ f(0)=3\)

therefore

the answer is the option

It is equal to \(3\) and represents the original number of saplings in Annie's garden.