Question

For an A.P. ,The first two term are -3, 4. The 21st term is

Answer 1

Answer:

The 21st term is 137.

Step-by-step explanation:

Arithmetic progression:

In an arithmetic progression the difference between consecutive terms is always the same, and its called common difference.

The nth term is given by:

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

In which $a_1$ is the first term and d is the common difference.

The first two terms are -3, 4.

This means that $a_1 = -3, d = 4 - (-3) = 7$

So

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

$a_n = -3 + 7(n-1)$

The 21st term is

$a_{21} = -3 + 7(21-1) = -3 + 140 = 137$

The 21st term is 137.