2*x + 1 ------- 3*x - 1
(2*x + 1)/(3*x - 1)
2/3 + 5/(3*(-1 + 3*x))
2 5 - + ------------ 3 3*(-1 + 3*x)
2 5 - + -------- 3 -3 + 9*x
2/3 + 5/(-3 + 9*x)
(1.0 + 2.0*x)/(-1.0 + 3.0*x)