2x(x-5)-2=12

Solution for 2x(x-5)-2=12 equation:

2x(x-5)-2=12

We move all terms to the left:

2x(x-5)-2-(12)=0

We add all the numbers together, and all the variables

2x(x-5)-14=0

We multiply parentheses

2x^2-10x-14=0

a = 2; b = -10; c = -14;
Δ = b2-4ac
Δ = -102-4·2·(-14)
Δ = 212
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:

$\sqrt{\Delta}=\sqrt{212}=\sqrt{4*53}=\sqrt{4}*\sqrt{53}=2\sqrt{53}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-10)-2\sqrt{53}}{2*2}=\frac{10-2\sqrt{53}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-10)+2\sqrt{53}}{2*2}=\frac{10+2\sqrt{53}}{4}
$