f(x) = x - 5
Substitute the values of x to the equation of the function f.
f(-1) = -1 - 5 = -6
f(0) = 0 - 5 = -5
f(1) = 1 - 5 = -4
f(2) = 2 - 5 = -3
f(5) = 5 - 5 = 0
f(8) = 8 - 5 = 3
