-8x^2-30x+18=0

Solution for -8x^2-30x+18=0 equation:

-8x^2-30x+18=0

a = -8; b = -30; c = +18;
Δ = b2-4ac
Δ = -302-4·(-8)·18
Δ = 1476
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:

$\sqrt{\Delta}=\sqrt{1476}=\sqrt{36*41}=\sqrt{36}*\sqrt{41}=6\sqrt{41}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-6\sqrt{41}}{2*-8}=\frac{30-6\sqrt{41}}{-16}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+6\sqrt{41}}{2*-8}=\frac{30+6\sqrt{41}}{-16}
$