Question

if 2nd and 5th terms of an arithmetic progression are 7 and 19 respectively, them the first term is​

Answer 1

2nd term 7

5th term 19

1th term 3

Answer 2

Given,

2nd term of AP = 7

5th term of AP = 19

To find,

The first term of AP.

Solution,

We can simply solve this mathematical problem by using the following mathematical process.

Let, the common difference of AP = x

Third term of AP = Second term of AP + common difference = 7+x

Similarly,

Fourth term of AP = 7+x+x

Fifth term of AP = 7+x+x+x = 7+3x

According to the data mentioned in the question,

7+3x = 19

3x = 19-7

3x = 12

x = 4

Common difference of AP = 4

Now,

First term of AP = Second term of AP - common difference = 7-4 = 3

Hence, first term is 3