x2-4.34x-17.28=0

Solution for x2-4.34x-17.28=0 equation:

x2-4.34x-17.28=0

We add all the numbers together, and all the variables

x^2-4.34x-17.28=0

a = 1; b = -4.34; c = -17.28;
Δ = b2-4ac
Δ = -4.342-4·1·(-17.28)
Δ = 87.9556
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{-(-4.34)-\sqrt{87.9556}}{2*1}=\frac{4.34-\sqrt{87.9556}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4.34)+\sqrt{87.9556}}{2*1}=\frac{4.34+\sqrt{87.9556}}{2}
$