We are given equation: y=ln(x) .
And translation is 5 units down.
We know the rule of transformation f(x) = y + k, if k is greater than 0 it would move up or if k is less than 0, it would move down.
For the given translation 5 unit down, 5 should be less than 0.
Number less than 0 are negative numbers.
So, we need to add -5 in the given function to ln(x).
So, we would get the final equation for five units down as
y =ln(x) - 5.