The given function f(x) is
We need to find
a) f(5)
It means finding the value of the y-coordinate in the ordered pair that has x-coordinate = 5
Look at the function
At x = 5, y = 5 (1st orderd pair), then
f(5) = 5
b) f(-8)
It means finding the value of the y-coordinate in the ordered pair that has x-coordinate = -8
Look at the function
At x = -8, y = 5, (last ordered pair), then
f(-8) = 5