Answer:
r = 12
Explanation:
First you need to get rid of 36 to leave 2r by itself. You do that by subtracting positive 36 minus 36 which cancels each other out. You do that to the other side. Which is going to be -12-36= -48. Then you get rid of the 6r by subtracting it by 6r. And you do that to 2r. Which is 2r-6r= -4r. You need to get rid of the -4 to leave r by itself so you divide by -4. And do the same to -48. So... -48/-4= 12
r = 12