Mathematics: Q7 In an AP, the first term is -12 and the last term is 40. If the sum of all terms is 196, find thecommon difference and number of terms.

Q7 In an AP, the first term is -12 and the last

daii128

01.02.2022

d = 4, n = 14

Step-by-step explanation:

$S_n=\dfrac{a_1+a_n}{2}\cdot n$

$\text{Given:}\quad S_n=196, a_1=-12, a_n=40\\\\\\196=\dfrac{-12+40}{2}\cdot n\\\\392=28n\\\\14=n$

$a_{n}=a_1+d(n-1)\\a_{14}=a_1+d(14-1)\\40=-12+d(14-1)\\52 = 13d\\4=d$

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cjjudecjude5675

20.06.2020

Step-by-step explanation:

Analysis

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