Question

64, –48, 36, –27, ...

Which formula can be used to describe the sequence?


f(x + 1) = Three-fourthsf(x)

f(x + 1) = Negative three-fourthsf(x)

f(x) = Three-fourthsf(x + 1)

f(x) = Negative three-fourthsf(x + 1)

Answer 1

a

Explanation:

Answer 2

f(x + 1) = -(3/4)*f(x)

(second option)

Explanation:

Here we have the sequence:

64, -48, 36, -27, ...

First, we can notice two things:

Each term has a different sign than the previous term, so the relation is something like:

f(x + 1) = -k*f(x)

Now to find the value of k, we can just replace some of the values (for example, the first and the second one)

-48 = -k*64

48/64 = k

3/4 = k

Now, if we use any pair of consecutive terms we should get the same value of k, now let's try to use the second and third terms to see if we get the same value of k:

36 = -k*(-48)

36 = k*48

36/48 = k

3/4 = k

We got the same value, so we can conclude that k = (3/4)

Then the relation that describes this sequence is:

f(x + 1) = -(3/4)*f(x)