Question

find the 23rd term of the AP7, 5,3,1,-1, 3
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Answer 1

$\sf\small{ \underline{\underline\red{ \pmb{Given:-}}}}$

• 7, 5,3, 1, -1, -3_______are in A.P

$\sf\small{ \underline{\underline\red{ \pmb{To \: Find:-}}}}$

• 23rd term of series

$\sf\small{ \underline{\underline\red{ \pmb{Solution:-}}}}$

• First term = a = 7.
• Last term No. of term term = n = 23
• difference = 5-7 =2

We know,

$\sf \:a + (n-1) d = l$

$\sf \longrightarrow \:77 +(23-1)(-2) = l$

$\sf \longrightarrow \: 77-2×22 = l$

$\sf \longrightarrow \: -37$

Therefore, 23rd term is -37.