Asequence is defined recursively using the formula f(n+1)=-0.5f(n). if the first term of the sequence is 120, what is f(5)?

f (5) = 7.5

Explanation:
The function given is:
f (n+1) = -0.5 f (n)

We are also given that:
first term is 120
This means that:
f (1) = 120

We will get the other terms by substitution as follows:
f (2) = -0.5 f (1) = -0.5(120) = -60
f (3) = -0.5 f(2) = -0.5(60) = 30
f (4) = -0.5 f(3) = -0.5(30) = -15
f (5) = -0.5 f(4) = -0.5(-15) = 7.5

Therefore, f (5) = 7.5

Hope this helps :)

Element 17 is chlorine it is a group 7 element(halogen) and belongs to period 3 of the periodic table