Step-by-step explanation:
Given the formula
a(n+1)=an−3
The first term a(1) = 31
For the second term
a(2)
We have
a( 1 + 1) = a(1) - 3
a(2) = 31 - 3
a(2) = 28
For the third term
a(3)
We have
a(2+1) = a(2) - 3
a(3) = 28 - 3
a(3) = 25
For the fourth term
a(4)
That's
a(3+1) = a(3) - 3
a(4) = 25 - 3
a(4) = 22
Hope this helps you