k2-18k+8=-9

Solution for k2-18k+8=-9 equation:

k2-18k+8=-9

We move all terms to the left:

k2-18k+8-(-9)=0

We add all the numbers together, and all the variables

k^2-18k+17=0

a = 1; b = -18; c = +17;
Δ = b2-4ac
Δ = -182-4·1·17
Δ = 256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{256}=16$
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-18)-16}{2*1}=\frac{2}{2}
=1
$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-18)+16}{2*1}=\frac{34}{2}
=17
$