Answer:
g(x) = -l2xl-4
Here are some extra tips for future use (This goes for any amount of units specified I'm just using 4 as an example):
If translated 4 units down it's negative so you subtract -4 at the end of the equation.
if translated 4 units up it's positive so you'd add +4 at the end of the equation.
If translated 4 units to the left you add those 4 units to the x-value so it would be f(x)= -l2x+4l.
If translated 4 units to the right you subtract 4 units to the x-value so it would be f(x)= -l2x-4l.
