Question

if first term of AP is 3 and d= 9 find 12th term of a AP​

Answer 1

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★ Given -

• First term of the A.P. (a) = 3
• Common Difference (d) = 9

★ To Find -

• 12 th term of the A.P.

★ Formula used -

• → n th term = a + (n - 1)d

★ Solution -

$\longrightarrow \: \rm \: 12th \: term \: = a \: + (12 - 1)d \\ \\ \longrightarrow \: \rm \: a_{12} \: = 3 + 11 \times 9 \\ \\ \longrightarrow \rm \: a_{12} \: = 3 + 99 \\ \\ \implies \rm \: \boxed{a_{12} = 102}$

Answer 2

Solution :

Formula:-

a12 = a1 + (12 - 1) d

Put the values

a12 = 3 + ( 12 - 1) × 9

= 3 + 11 × 9

= 3 + 99

a12 = 102