0.375-0.15x-0.108x^2=0

Solution for 0.375-0.15x-0.108x^2=0 equation:

0.375-0.15x-0.108x^2=0

a = -0.108; b = -0.15; c = +0.375;
Δ = b2-4ac
Δ = -0.152-4·(-0.108)·0.375
Δ = 0.1845
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-0.15)-\sqrt{0.1845}}{2*-0.108}=\frac{0.15-\sqrt{0.1845}}{-0.216}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.15)+\sqrt{0.1845}}{2*-0.108}=\frac{0.15+\sqrt{0.1845}}{-0.216}
$