Question

What is we do whether the question is be in point ex:a=-18.9,d=2.5,an=3.6 n=?
In arithmetic progressions

Answer 1

Answer:

an = a+(n-1)d

3.6=-18.9+(n-1)2.5

3.6+18.9=(n-1)2.5

22.5= (n-1)2.5

22.5/2.5=n-1

9=n-1

n=9+1

n=10

i hope it helps