9n^2+3n-13=0

Solution for 9n^2+3n-13=0 equation:

9n^2+3n-13=0

a = 9; b = 3; c = -13;
Δ = b2-4ac
Δ = 32-4·9·(-13)
Δ = 477
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{477}=\sqrt{9*53}=\sqrt{9}*\sqrt{53}=3\sqrt{53}$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(3)-3\sqrt{53}}{2*9}=\frac{-3-3\sqrt{53}}{18}
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+3\sqrt{53}}{2*9}=\frac{-3+3\sqrt{53}}{18}
$