Question

if the first and last term of an ap is 10 and - 10 how many terms are there? givan that d=(-1)​

Answer 1

a=10

l=-10

d=-1

l= a+ (n-1) d

-10= 10 +(n-1)×-1

-20=-n+1

-21=-n

n=21

hope it helps

Answer 2

Step-by-step explanation:

a=10

last term=-10

d=-1

n=21