Find the 20th term of the arithmetic sequence

-99

Step-by-step explanation:

Given :

Arithmetic sequence : 15 , 9 ,3 , -3 , ........

To Find : 20th term .

Solution :

Formula of nth term in Arithmetic mean :  ---(A)

where

a = first term of sequence

n = term position

d = common difference

= the term you want to find

Thus in the given sequence:

a = 15 ( first term )

n = 20 th term ( given )

d = 9-15 = 3-9 = -6(common difference)

Putting values in (A)

⇒

Hence the 20th term is -99 i.e. option 1

the answer is b.)

< 1=< 2

20%

step-by-step explanation: