(x-18)x-2=42

Solution for (x-18)x-2=42 equation:

(x-18)x-2=42

We move all terms to the left:

(x-18)x-2-(42)=0

We add all the numbers together, and all the variables

(x-18)x-44=0

We multiply parentheses

x^2-18x-44=0

a = 1; b = -18; c = -44;
Δ = b2-4ac
Δ = -182-4·1·(-44)
Δ = 500
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:

$\sqrt{\Delta}=\sqrt{500}=\sqrt{100*5}=\sqrt{100}*\sqrt{5}=10\sqrt{5}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-18)-10\sqrt{5}}{2*1}=\frac{18-10\sqrt{5}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-18)+10\sqrt{5}}{2*1}=\frac{18+10\sqrt{5}}{2}
$