Question

Find the 20th term in the arithmetic sequence.
−4, 1, 6, 11, 16, ...

Answer 1

So you're adding 5.
-4, 1, 6, 11, 16, 21, 26, 31, 36, 41, 46, 51, 56, 61, 66, 71, 76, 81, 86, 91

91 is the 20th term :)

Answer 2

The 20th term in the arithmetic sequence is 91

What is an arithmetic sequence?

"A sequence of numbers where the differences between every two consecutive terms is the same."

What is common difference in arithmetic sequence?

"The difference between consecutive numbers in an arithmetic sequence."

Formula for the n-th term of an arithmetic sequence:

$a_n = a_1 + (n- 1)d$

where $a_1$ is the first term of an arithmetic sequence.

d is the common difference

For given question,

We have been given an arithmetic sequence -4, 1, 6, 11, 16, . . .

The first term of given arithmetic sequence is $a_1=4$

First we find the common difference for given arithmetic sequence.

Consider the difference between consecutive terms,

1 - (-4) = 5

6 - 1 = 5

11 - 6 = 5

The common difference for given arithmetic sequence d = 5

We need to find the 20th term in the arithmetic sequence.

Using the formula for the n-th term of an arithmetic sequence,

for n = 20

$\Rightarrow a_{20}$

= - 4 + (20 - 1)(5)

= - 4 + (19 × 5)

= - 4 + 95

= 91

Therefore, the 20th term in the arithmetic sequence is 91

Learn more about an arithmetic sequence here:

https://brainly.com/question/10396151

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