Question

Use the sequence below to complete each task. 34, 25, 16, 7, ... a. Identify the common difference (a). b. Write an equation to represent the sequence. c. Find the 20th term (azo)

Answer 1

Problem

Solution

We have the following sequence of terms 34,25,16,7,....

Part a

The common difference for this case would be:

25-34= -9

16-25=-9

7-16= -9

Then the answer for part a would be -9

Part b

We want to write the following form:

an = a1 + (n-1) d

For this case d=-9, a1= 34

And then we can write the genral expression like this:

an = 34 + (n-1 ) (-9)

With n = 1,2,3,4....

Part c

In order to find the 20 th term we can replace n =20 and we got:

a20= 34 + (20-1) (-9) = 34-171= -137