Read the directions for exersizes 23 and 14. look at !

This is an arithmetic sequence because each term is 9 more than the previous term, called the common difference.  The equation for an arithmetic sequence is:

a(n)=a+d(n-1), a=initial term, d=common difference, n=term number...

In this case a=9 and d=9 so

a(n)=9+9(n-1)

a(n)=9+9n-9

a(n)=9n

So for any term n, a(n)=9n

...

a(16)=9*16=144

Teri ma ki chhut‌‌‌‌‌‌