x^2+2.2x-2.2=0

Solution for x^2+2.2x-2.2=0 equation:

x^2+2.2x-2.2=0

a = 1; b = 2.2; c = -2.2;
Δ = b2-4ac
Δ = 2.22-4·1·(-2.2)
Δ = 13.64
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{-(2.2)-\sqrt{13.64}}{2*1}=\frac{-2.2-\sqrt{13.64}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2.2)+\sqrt{13.64}}{2*1}=\frac{-2.2+\sqrt{13.64}}{2}
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