Question

compare the graphs of y=f(x) and y=-f(x)

Answer 1

f(x) is another way to name "y"
soo... it's like saying y=y, and y=-y, perhaps the difference is one graph is positive and the other is negative... just an idea. hope you get a good answer.

Answer 2

f(x) is a graph. All -f(x) does is rotate it around the x axis.