Question

which term of AP 5,9,13,17--------is 81​

Answer 1

[HeY Mate]

$\huge\bold\red{Answer}$

Given

• First term (a) = 5
• Common difference(d)=9-5=4
• n = 81

To Find

• a81 = ?

Solution

$\tt \implies \: a_{n} = a + (n - 1)d \\ \tt \implies \: a_{81} = 5 + (81 - 1)4 \\ \tt \implies \: a_{81} = 5 + 320 \\ \tt \implies \: a_{</u><u>8</u><u>1</u><u>} = 325$

I Hope It Helps You✌️

Answer 2

$\huge\mathfrak\green{Hello\:Dear}$

$\orange{\boxed{\bold{Given}}}$

First term (a) = 5

Common difference (d) = 4

number of terms (n) = 81

We have to find $\bold a_{n}$

$\red{\boxed{\bold{Solution}}}$

Using formula,

$a_{n} = a + (n - 1)d \\ a_{81} = 5 + (81 - 1)4 \\ a_{81} = 5 + 80 \times 4 \\ a_{81} = 5 + 320 \\ a_{81} = 325$

$\huge\mathbb\blue{THANK\:YUH!}$