Question

if an AP the common difference and 7th term is 4 then find the first term

Answer 1

↑ Here is your answer ↓
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Given: The 7th term and common difference is '4'.

$a_7 = a + 6d$

$4 = a + 6(4)$

$4 = a + 24$

$a = 4 - 24$

$a = -20$ 

Answer 2

Hello friend, 
Here's your answer:




Given:
7th term = common difference (d) = 4


As 

Nth term of an AP = first term (a) +(n - 1)d

Therefore 

7th term = a + (7 - 1)d 
=> 7th term = a + 6d

By substituting the values:

=> 4 = a + 6*4
=> 4 = a + 24.

Transposing the term 24, we get

=> a = 4 - 24 = -20
Therefore the first term of the AP is -20.




Hope my answer helps you. 
@GeniusYH