What kind of slope does this line have? $x\ =\ -5$  

Undefined slope (vertical lines) name begin with what letter?

What kind of slope does this line have? $4\ =\ x$  

What kind of slope does this line have? $9\ =\ y$  

What kind of slope does this line have? $y\ =\ 8\ -\ x$  

Name this line!

What variable does it have in common? (it must begin with that letter)

Name this line!

What variable does it have in common? (it must begin with that letter)

Zero slope (horizontal lines) name begin with what letter?