2x^2-90x-225=0

Solution for 2x^2-90x-225=0 equation:

2x^2-90x-225=0

a = 2; b = -90; c = -225;
Δ = b2-4ac
Δ = -902-4·2·(-225)
Δ = 9900
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:

$\sqrt{\Delta}=\sqrt{9900}=\sqrt{900*11}=\sqrt{900}*\sqrt{11}=30\sqrt{11}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-90)-30\sqrt{11}}{2*2}=\frac{90-30\sqrt{11}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-90)+30\sqrt{11}}{2*2}=\frac{90+30\sqrt{11}}{4}
$