Question

for an AP, the 7th term is -1 and 16th term is 17. fing the general term of the AP

Answer 1

$a + 6d = - 1 \\ a + 16d = 17 \\ subtacting \: equation \: 1from \: 2 \: we \: get \\ 10d = 18 \\ d = 1.8 \\ a = 17 - (16 \times 1.8) \\ a = - 11.8 \\ general \: term = - 11.8 + (n - 1)1.8$

Answer 2

Hey here's your answer!

First term = a

Difference = d

- 1 = a + d(6) ---------------> By formula nth term = a + d(n - 1)

-1 = a + 6d ------------> (1)

17 = a + 15d ----------- (2)

Subtracting equation 2 from 1,

-18 = -9d

d = 2

So by substituting d = 2 in equation 1, we get a = -13

nth term = -13 + 2(n - 1)

              = -13 + 2n - 2

Therefore nth term = 2n - 15

Hope this helps! :)