Question

Which function describes the arithmetic sequence shown?

3, 1, −1, −3, −5, −7, ...
A) ƒ(x) = 2x + 5
B) ƒ(x) = 2x − 5
C) ƒ(x) = −2x + 5
D) ƒ(x) = −2x − 5

Answer 1

Answer: C.) f(x) = -2x + 5

If you start from x=1, you will see the patter follows -2x + 5

-2(1) +5 = -2+5 = 3
-2(2)+ 5 = -4 + 5 = 1
-2(3) + 5= -6 +5 = -1
And so on...

Answer 2

Answer: Option 'c' is correct.

Explanation:

Since we have given that

3, 1, −1, −3, −5, −7, ...

Here, a = 3

d = a₂-a₁=1-3=-2

Let the number of terms be 'x'.

As we know the formula for "Arithmetic sequence":

`f(x)=a+(x-1)d\\\\f(x)=3-2(x-1)\\\\f(x)=3-2x+2\\\\f(x)=-2x+5`

Hence, Option 'c' is correct.