Question

For the arithmetic sequence 42, 32, 22, 12... find the 18th term.

Answer 1

Answer:

The18th term of the given sequence is -128

Explanation:

To find the 18th term of the sequence:

42, 32, 22, 12, ..., we need to find the nth term of the sequence first.

The nth term of a sequence is given be the formula:

$T_n=a+(n-1)d$

Where a is the first term, and d is the common difference.

Here, a = 42, d = 32 - 42 = -10

$\begin{gathered} T_n=42+(n-1)(-10) \\ =42-10n+10 \\ T_n=52-10n \end{gathered}$

To find the 18th terem, substitute n = 18 into the nth term

$\begin{gathered} T_{18}=52-10(18) \\ =52-180 \\ =-128 \end{gathered}$