Question

The (n-1)th term of an AP is given by 7,12,17,22....is

Answer 1

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$question \: -$

☞The (n —1)^th term of an A. P. 7, 12, 17 , 22,... is

Answer —

$→here \\ a = 7 \: and \: \\ d \: = 12 - 7 \: = 5 \\ d = 5$

$☞formula \: used \: - \\ an \: = a + (n \: - 1)d$

$→a + (n - 1)d \\ \\ 7 +{ (n - 1) - 1}(5)$

$becoz \: n \: = (n - 1) \: \: \: (given)$

$→7 + (n - 2)5$

$→7 + 5n - 10$

$→5n - 3$

Answer = 5n—3

hope it is helpful for you ✅✔☑

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Answer 2

Let the given AP terms be

$a0 = 7 \\ a1 = 12 \\ a2 = 17 \\ a3 = 22 \\ . \\ . \\ .$

We need to find the

$(n - 1)th \: term$

We know that

$an = a + (n - 1)d$

Here,

$a = first \: term = 7 \\ d = common \: dfference \\ = a1 - a0 \\ = 12 - 7 \\ = 5 \\ n = the \: term \: we \: need \: to \: find \: out = n - 1$

Now,

$a(n - 1) = a + (n - 1 - 1)d \\ = 7 + (n - 2)5 \\ = 7 + 5n - 10 \\ = 5n - 3$

Therefore, (n-1)th term of the given AP series is

$a(n - 1) = 5n - 3$

#SPJ2