5x2-15x-30=0

Solution for 5x2-15x-30=0 equation:

5x^2-15x-30=0

a = 5; b = -15; c = -30;
Δ = b2-4ac
Δ = -152-4·5·(-30)
Δ = 825
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:

$\sqrt{\Delta}=\sqrt{825}=\sqrt{25*33}=\sqrt{25}*\sqrt{33}=5\sqrt{33}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-15)-5\sqrt{33}}{2*5}=\frac{15-5\sqrt{33}}{10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+5\sqrt{33}}{2*5}=\frac{15+5\sqrt{33}}{10}
$