The reason why f(1) = -20 - 5 is because of the given function formula f(0) = -20 and f(n) = f(n - 1) - 5 for n ≥ 1.
How to use input value in a function?
We are told that the sequence is defined as;
f(0) = -20
f(n) = f(n - 1) - 5 for n ≥ 1
Using that formula above we can say that;
f(1) = f(1 - 1) - 5
f(1) = f(0) - 5
Thus;
f(1) = -20 - 5
Similarly;
f(2) = f(2 - 1) - 5
f(2) = f(1) - 5
Thus;
f(2) = -20 - 5 - 5
Similarly;
f(3) = f(3 - 1) - 5
f(3) = f(2) - 5
Thus;
f(2) = -20 - 5 - 5 - 5
Read more about Function Input Value at; https://brainly.com/question/10283950
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