Question

1. Find the 20'; 25" and nth term of the A.P. given by 21, 16, 11,6, 1,-4.-9​

Answer 1

Step-by-step explanation:

Here d=16-21=-5

nth term = a+(n-1)d=21+(n-1)(-5)

=21-5n+5

=25-5n

20th term=21+(20-1)(-5)

=21-95

=(-74)

25th term=21+(25-1)(-5)

=21-120

=(-99)