If f(x) = x^2, which of the following describes the graph of f(x) - 5?
a.) the graph of f(x) - 5 is a vertical shift of f(x) = x^2 five units up.
b.) the graph of f(x) - 5 is a horizontal shift of f(x) = x^2 five units to the left.
c.) the graph of f(x) - 5 is a vertical shift of f(x) = x^2 five units down.
d.) the graph of f(x) - 5 is a horizontal shift of f(x) = x^2 five units to the right.

In any given equation, a positive or negative number that isn't multiplied by a variable is called "b", or "y-intercept." Seeing as y-5 (f(x) is the same as y) isn't an equation, it probably means you need to add 5 to both sides to isolate y.
you end up with y=5, a horizontal line in which every "y" value in every set of points is equal to 5
Ex: (1,5),(2,5),(3,5)...
this means that your parent function of y=0 has a vertical shift upwards of five. hope I could help :)