Answer:
Hey There!
Let's solve...
First we need to find out the equation of x which is

Now let's find out the equation of y which is

Now let's find out equation of z which is

On adding the three equations, we get

Now we get..

Now let's find our the average of x,y snd z which is


Now simplify..

So answer is m+7
I hope it is helpful to you..
Cheers!____________