X2-18x=2

Solution for X2-18x=2 equation:

X2-18X=2

We move all terms to the left:

X2-18X-(2)=0

We add all the numbers together, and all the variables

X^2-18X-2=0

a = 1; b = -18; c = -2;
Δ = b2-4ac
Δ = -182-4·1·(-2)
Δ = 332
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{332}=\sqrt{4*83}=\sqrt{4}*\sqrt{83}=2\sqrt{83}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-18)-2\sqrt{83}}{2*1}=\frac{18-2\sqrt{83}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-18)+2\sqrt{83}}{2*1}=\frac{18+2\sqrt{83}}{2}
$