9x^2-26x-39=0

Solution for 9x^2-26x-39=0 equation:

9x^2-26x-39=0

a = 9; b = -26; c = -39;
Δ = b2-4ac
Δ = -262-4·9·(-39)
Δ = 2080
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{2080}=\sqrt{16*130}=\sqrt{16}*\sqrt{130}=4\sqrt{130}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-26)-4\sqrt{130}}{2*9}=\frac{26-4\sqrt{130}}{18}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-26)+4\sqrt{130}}{2*9}=\frac{26+4\sqrt{130}}{18}
$