2(2r-1)/6+3=3(r+7)/18
I'm taking literally what you wrote which is
2(2r -1) 3(r + 7 )
______ + 3 = _______ multiply through by 18 to clear the fractions
6 18
3 [ 2(2r -1) ] + 54 = 3(r + 7 ) simplify
12r - 6 + 54 = 3r + 21
12r + 48 = 3r + 21 subtract 3r, 48 from both sides
9r = -27 divide both sides by 9
r = -3