
Notice that if

is a root so is

(Admin Sir, could you kindly see that the latex output comes inline with the text)
Both 1 and -1 are roots of the equation (That the product of roots is -1 also tells us that -1 is necessarily is a root)
Now  = 133(x^5- x) = 133x (x^4-1))
(x^4%2Bx^2%2B1) = 133x(x^2-1) (x^2%2B1))
(Since we have already noted that
are roots)

%2B\frac{78}{x^2%2B1} = 133x%2B78)
)

and since the reciprocal is also a root we must also have

This means if x is a real root, then
Now from rational roots theorem if x is a rational root of the equation, then

where p and q are both integer divisors of 78.
Here the real roots are positive. The factors of 78 to be considered are 1,2, 3, 6, 13, 26,39, 78
You can easily see that none of the fractions formed by these numbersother than
satisfy the condition mentioned above. A quick check reveals that
and hence
are roots
Hence the rational roots are
,
and 
Hence the sum of rational roots is 