The new equation, after translating the original function downward by three units, is

When you translate a function downward, you subtract a constant from the original function.
In this case, the original function is
, and you want to translate it downward by three units.
So, you subtract 3 from the function. The new equation would be:

Simplifying this expression, you get:

Therefore, the new equation, after translating the original function downward by three units, is
