2<span>(<span>log4</span><span>(3)</span>+<span>log4</span><span>(x)</span>+<span>log4</span><span>(y)</span>+<span>log4</span><span>(z)</span><span>)</span></span>
Step-by-step explanation:

A line on this coordinate plane is horizontal when every input (x) has the same output y).
This function always gives the same output with no matter what input you put it in.
You should scan it on this app:)