0,15x^2-90x+1000=0

Solution for 0,15x^2-90x+1000=0 equation:

0.15x^2-90x+1000=0

a = 0.15; b = -90; c = +1000;
Δ = b2-4ac
Δ = -902-4·0.15·1000
Δ = 7500
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:

$\sqrt{\Delta}=\sqrt{7500}=\sqrt{2500*3}=\sqrt{2500}*\sqrt{3}=50\sqrt{3}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-90)-50\sqrt{3}}{2*0.15}=\frac{90-50\sqrt{3}}{0.3}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-90)+50\sqrt{3}}{2*0.15}=\frac{90+50\sqrt{3}}{0.3}
$