Happy 18th!

Solve z in the following and you'll catch up with me :-)

x=Mike's Age in years

z=(x*y)+(y*y)




>Well, it was my 18th birthday yesterday, and I got ... a shave and a haircut, and just when I was about to look like my picture again.
>
>Anyways, I also bought myself a SprintPCS phone (remember that thread oh so long ago) and the Jimmy Page & Black Crowes concert album, sweeet....