Question

Which of the term of A.P 5,2,-1 is -49

Answer 1

First term= 5
common diff. = -3
Therefore,
-49 = 5 + ( n - 1) * -3
-49 - 5 = ( n - 1 ) * -3
- 54 / - 3 = ( n - 1 )
18 = n - 1
n = 18 + 1
n = 19
19 th term is -49.

Answer 2

Answer:

19th term

Step-by-step explanation:

Given : A.P. :  5,2,-1

To Find: Which of the term of A.P is -49

Solution:

a = first term = 5

d = common difference = 2-5=-1-2= -3

Formula of nth term in A.P. = $a_n=a+(n-1)d$

Now to find n for -49

$-49=5+(n-1)(-3)$

$-49=5-3n+3$

$-49=8-3n$

$-49-8=-3n$

$-57=-3n$

$\frac{-57}{-3}=n$

$19=n$

Hence 19th term of given A.P. is -49