Question

Find the 25th term of the arithmetic sequence whose common difference is d=−5 and whose first term is a1=2 (picture is for reference)

Answer 1

The common difference of the Airthmetic sequence d=(-5)

First term of the series =2

The standard form for the n term in the AP series is

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

Here, we have

$n=25,a_1=2,\text{ d=(-5)}$

Subsitute the values,

$\begin{gathered} a_{25}=2+(25-1)(-5) \\ a_{25}=2+24(-5) \\ a_{25}=2-120 \\ a_{25}=-118 \end{gathered}$

The 25th term is -118.

ANSWER : -118