X^2-6.2x-1.8=0

Solution for X^2-6.2x-1.8=0 equation:

X^2-6.2X-1.8=0

a = 1; b = -6.2; c = -1.8;
Δ = b2-4ac
Δ = -6.22-4·1·(-1.8)
Δ = 45.64
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{-(-6.2)-\sqrt{45.64}}{2*1}=\frac{6.2-\sqrt{45.64}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6.2)+\sqrt{45.64}}{2*1}=\frac{6.2+\sqrt{45.64}}{2}
$