Question

A sequence is defined by the recursive formula f (n + 1) = f(n) – 2. If f(1) = 18, what is f(5)?

Answer 1

real anwser is 10

Explanation:

toom the test

Answer 2

sub n=1
f(1+1) = f(1)-2 = 18
f(1) = 20
f(2) - f(1) = -2 , d=-2
f(5) = 20+d*(n-1) = 20+(-2)*(5-1) = 20-8 = 12