x^2-1.25x-2=0

Solution for x^2-1.25x-2=0 equation:

x^2-1.25x-2=0

a = 1; b = -1.25; c = -2;
Δ = b2-4ac
Δ = -1.252-4·1·(-2)
Δ = 9.5625
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{-(-1.25)-\sqrt{9.5625}}{2*1}=\frac{1.25-\sqrt{9.5625}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1.25)+\sqrt{9.5625}}{2*1}=\frac{1.25+\sqrt{9.5625}}{2}
$