Answer:
[tex]r=-6[/tex]
Step-by-step explanation:
First, we need to subtract 6 from each side, so that we can begin to isolate r.
[tex]18=6-2r\\\\12=-2r[/tex]
Next, we can divide each side by -2
[tex]12=-2r\\\\\frac{12}{-2} =\frac{-2r}{-2} \\\\-6=r[/tex]
