1,2x2-0,6x-10,2=0

Solution for 1,2x2-0,6x-10,2=0 equation:

1.2x^2-0.6x-10.2=0

a = 1.2; b = -0.6; c = -10.2;
Δ = b2-4ac
Δ = -0.62-4·1.2·(-10.2)
Δ = 49.32
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{-(-0.6)-\sqrt{49.32}}{2*1.2}=\frac{0.6-\sqrt{49.32}}{2.4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.6)+\sqrt{49.32}}{2*1.2}=\frac{0.6+\sqrt{49.32}}{2.4}
$