Question

find the 15th term of the A.P with second term 11 and common difference 9

Answer 1

Second term of a.p = a + (2-1)×d = a + d = 11

Common difference = d = 9

Therefore a = 11-9 = 2

Hence 15th term = a + 14d = 2+126=128 ANSWER........

THANK U ★★★
#CKC

Answer 2

Hello Dear.

Here is the answer---

Given ⇒

2nd term of the A.P. (T₂) = 11
Common Difference(d) = 9

Now, Using the Formula,
 Tₐ = a + (n - 1)d
Where, a = first term of the Arithmetic Sequence.

T₂ = a + (2 - 1)d
11 = a + 1 × 9
11  = a + 9
a = 11 - 9
 a = 2

∴ First Term of the A.P. = 2

Now, For 15th term,
 n = 15

∵  T₁₅ = a + (n - 1)d
∴ T₁₅ = 2 + (15 - 1)9
∴ T₁₅ = 2 + 14 × 9
⇒ T₁₅ = 2 + 126
⇒ T₁₅ = 128

Now, the Fifteenth term of the Arithmetic Progression is 128.


Hope it helps.