What are the step to help solve for
5r+30/20= 3r-36/3
the LCD is 60, so multiply each term by 60
300r + 90 = 180r - 720
120r = -810
r = -810/120 = -387/4
If on the other hand, you meant
(5r+30)/20 = (3r-36)/3
then
60r - 720 = 15r + 90
45r = 810
r = 18
notice how important it is to put in brackets to establish the correct order of operation?