Question

(b) Find the 20th, 25th and nth terms of the A.P. given by 21, 16, 11, 6, 1, - 4,- 9, ...​

Answer 1

Answer:

20th term is - 93 and 25th term is - 99.

And nth term is 26 - 5n

Step-by-step explanation:

• 20th term = a + 19d, here a = 21 and d = 16 - 21 = - 5. Therefore, 20th term = 21 + 19 (-5) = - 93
• Similarly, 25th term = a + 24d. Therefore, 25th term = 21 +24(-5) = - 99
• Now nth term = a + (n - 1) d = 21 + (n - 1)(-5) therefore nth term = 26 - 5n . I hope it will help you. Thank you