Question

In an
ap
a = 18 d= - 3
an = 0 Then the value n
​

Answer 1

Answer:

21

Step-by-step explanation:

an= a+(n-1)d

0= 18+(n-1)-3

0= 18-3n+3

0= 21+3n

-21= 3n

n= -21/3

n= -7

Answer 2

Answer:

an=a+(n-1)d

0=18+(n-1)(-3)

0=18-3n+3

18=3n+3

18-3=3n

15=3n

15/3=n

5=n