Simple Equation confusion

Hey guys;

I'm new to the forum so hello from me. I'm currently practicing simple linear-equations and feel comfortable with one and two-step equations.

However I've come across a slight obstacle with equations represented as thus;

17-y

_____ = 4.5

3

With this equation do I turn the denominator (3) across to 4.5 x (3) to make 13.5.

17-y = 13.5

The next step is where i become confused. I google-answered this example and the steps are;

17-y = 13.5

-y = -3.5

y= 3.5

How do i get 3.5? I've tried dividing 13.5 into 17 which is obviously wrong. Would be very grateful if someone could explain this to me.

thanks

J