30x^2-60x-90=0

Solution for 30x^2-60x-90=0 equation:

30x^2-60x-90=0

a = 30; b = -60; c = -90;
Δ = b2-4ac
Δ = -602-4·30·(-90)
Δ = 14400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{14400}=120$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-60)-120}{2*30}=\frac{-60}{60}
=-1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-60)+120}{2*30}=\frac{180}{60}
=3
$