First off, you want to get the r alone. To do this you can subtract the 4 from both sides. It should look like this. -12r+4-4=100-4 So you then get -12r=96, So next you divide by -12 on both sides. It will now look like this -12r divided by -12=96 divided by -12. So the final answer is r=-8
I hope this helped!
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