18x^2-42x-240=0

Solution for 18x^2-42x-240=0 equation:

18x^2-42x-240=0

a = 18; b = -42; c = -240;
Δ = b2-4ac
Δ = -422-4·18·(-240)
Δ = 19044
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{19044}=138$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-42)-138}{2*18}=\frac{-96}{36}
=-2+2/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-42)+138}{2*18}=\frac{180}{36}
=5
$