Answer:
r = -9
Step-by-step explanation:
First we want to ge the rs in the same place:
[tex]3r-7r=6+30[/tex]
[tex]-4r = 36[/tex]
[tex]r=-9[/tex]
r= -9
[tex]3r-30=6+7r\\Collect like terms\\3r-7r= 6+30\\-4r = 36\\Divide both sides by -4\\r = -9[/tex]
