Question

If nth term of an ap is 7-4n.Then find its common difference

Answer 1

An= 7-4n

A1=7-4
=3

A2=7-4×2
=-1

Common difference= A2-A1
=-1-3
=-4
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Answer 2

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$\large\mathsf\red{What \ is \ A.P. \ ?}$

$\mathsf\blue{A.P. \ is \ a \ sequence \ of \ numbers \ such \ that}$
$\mathsf\blue{the \ difference \ between \ the \ consecutive}$
$\mathsf\blue{terms \ is \ constant.}$

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$\huge\mathfrak{Solution :}$

$\large\mathsf\pink{Given \ -}$

${a_n}$$\mathsf{= \ 7 - 4n}$

$\large\mathsf\green{Putting \ n \ = \ 1}$

${a_1}$$\mathsf{= \ 7 - 4(1)}$

${a_1}$$\mathsf{= \ 3}$

$\large\mathsf\green{Putting \ n \ = \ 2}$

${a_2}$$\mathsf{= \ 7 - 4(2)}$

${a_2}$$\mathsf{= \ -1}$

$\mathsf{Now,}$

$\mathsf{Common \ Difference \ -}$

${a_2}$$\mathsf{-}$${a_1}$

$\large\mathsf\green{Putting \ values}$

$\mathsf{= \ -1 - (3)}$

$\mathsf{= \ -1 - 3}$

$\mathsf{= \ -4}$

$\large\textbf\pink{\boxed{d = -4}}$

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