Question

9. How many terms are there in the AP 18, 152, 13,.,-477
10. Which term of the AP 3, 8, 13, 18, ... is 88?
11. Which term of the AP 72, 68, 64, 60, ... is 0?
12. Which term of the AP,1,12,13,... 15 3?
13. Which term of the AP 21, 18, 15, ... is -81?

please answer q9 and any one of remaining questions​

Answer 1

11.

a = 72

d = 68-72= (-4)

an = 0

an = a + (n-1)d

0 = 72 + (n-1)(-4)

0 - 72 = (n-1)(-4)

(-72) = (n-1)(-4)

(-72)/(-4) = (n-1)

18 = n-1

18 + 1 = n

19 = n

The 19th term of an A.P is 0

Hope this help u

and plz send the Ques 9 properly