(x+1)/2 = (y+3)/4 + (x+y)/5, 10(x+1) = 5(y+3) + 4(x+y), 6x = 9y + 5, (3x + 2y + 1)/(x + 2y + 3) = (6x + 4y + 2)/(6x + 12y + 18)*(6/2) = 3[9y + 5 + 4y + 2]/[9y + 5 + 12y + 18] = 3[13y + 7]/[21y + 23]
