(13x-143)/2 = (3x+33)/3
(13x-143)/2-(3x+33)/3 = 0
(13x-143)*3/2*3-(3x+33)*2/3*2 = 0
(39x-429)/6-(6x+66)/6 = 0
(33x-495/6 = 0
33x/6-495/6 = 0
(11/2)*x = 495/6
x = (495/6)*(2/11) = 15
