You get this answer by simply sticking a negative out front of the original function. In other words, g(x) = -f(x) or more technically, g(x) = -1*f(x).
The negative will flip every y coordinate from positive to negative (or vice versa)
You'll also use the idea that |2x| = 2|x|. The two can be pulled out since we can say |x*y| = |x|*|y| So |2*x| = |2|*|x| = 2|x|
