Question

*What is the common difference of an AP (-15, -7, 1, 9, ..................)?*

1️⃣ -15
2️⃣ -8
3️⃣ 8
4️⃣ -7
​

Answer 1

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A.P : -15, -7, 1, 9,........

$\large{a}_{1}\:=\:(-15)$

$\large{a}_{2}\:=\:(-7)$

A.T.Q.

d = $\large{a}_{2}\:-\:{a}_{1}$

= (-7) - (-15)

= (-7) + 15

= (8)

✯ More to know :-

• $\large{a}_{n}\:=\:a(n-1)d$
• D = $\large{a}_{2}\:-\:{a}_{1}$

Answer 2

8

t2 - t1 = - 7 - (- 15) = - 7 + 15 = 8