x^2-0.73*x-0.73^2=0

Solution for x^2-0.73*x-0.73^2=0 equation:

x^2-0.73x-0.73^2=0

We add all the numbers together, and all the variables

x^2-0.73x-0.5329=0

a = 1; b = -0.73; c = -0.5329;
Δ = b2-4ac
Δ = -0.732-4·1·(-0.5329)
Δ = 2.6645
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{-(-0.73)-\sqrt{2.6645}}{2*1}=\frac{0.73-\sqrt{2.6645}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.73)+\sqrt{2.6645}}{2*1}=\frac{0.73+\sqrt{2.6645}}{2}
$