Question

please solve this Que 14)

Answer 1

a+( n-1)d=a+(n-1)d
24+(n-1)-4=-11+(n-1)3
35-4n+4=3n-3
7n=42
n=6

Answer 2

AP series = 24, 20, 16, 12 ....

⇒ First Term = a1 = 24

⇒ Common Difference = d = 20 - 24 = -4

Find the nth term:

an = a1 + (n - 1)d

an = 24 + (n - 1 ) (- 4)

an = 24 - 4n + 4

an = 28 - 4n

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AP series = -11, -8, -5, -2 ....

⇒ First Term = a1 = -11

⇒  Common Difference = d = -8 - (-11) = 3

Find the nth term:

an = a1 + (n - 1)d

an = -11 + (n - 1)(3)

an = -11 + 3n - 3

an = 3n - 14

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Since the two nth term is the same:

28 - 4n = 3n - 14

4n + 3n = 28 + 14

7n = 42

n = 42 ÷ 7

n = 6

Answer: n = 6