2 4 x - - 9
x^2 - 4/9
(x + 2/3)*(x - 2/3)
2 -4 + 9*x --------- 9
(-4 + 9*x^2)/9
-0.444444444444444 + x^2
(-2 + 3*x)*(2 + 3*x) -------------------- 9
(-2 + 3*x)*(2 + 3*x)/9