From the problem, we have :
The nature of the roots depends on the value of b^2 - 4ac.
If the result is greater than or equal to 0, the roots are rational.
If the result is less than 0, the roots are irrational.
From the equation, we have :
a = 6, b = -8 and c = -8
Since the result is greater than 0, the roots are rational.