2x^2+5.5x-20=0

Solution for 2x^2+5.5x-20=0 equation:

2x^2+5.5x-20=0

a = 2; b = 5.5; c = -20;
Δ = b2-4ac
Δ = 5.52-4·2·(-20)
Δ = 190.25
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{-(5.5)-\sqrt{190.25}}{2*2}=\frac{-5.5-\sqrt{190.25}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5.5)+\sqrt{190.25}}{2*2}=\frac{-5.5+\sqrt{190.25}}{4}
$