-30x^2+18x-0.8=0

Solution for -30x^2+18x-0.8=0 equation:

-30x^2+18x-0.8=0

a = -30; b = 18; c = -0.8;
Δ = b2-4ac
Δ = 182-4·(-30)·(-0.8)
Δ = 228
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:

$\sqrt{\Delta}=\sqrt{228}=\sqrt{4*57}=\sqrt{4}*\sqrt{57}=2\sqrt{57}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-2\sqrt{57}}{2*-30}=\frac{-18-2\sqrt{57}}{-60}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+2\sqrt{57}}{2*-30}=\frac{-18+2\sqrt{57}}{-60}
$