x2+12x=3

Solution for x2+12x=3 equation:

x2+12x=3

We move all terms to the left:

x2+12x-(3)=0

We add all the numbers together, and all the variables

x^2+12x-3=0

a = 1; b = 12; c = -3;
Δ = b2-4ac
Δ = 122-4·1·(-3)
Δ = 156
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:

$\sqrt{\Delta}=\sqrt{156}=\sqrt{4*39}=\sqrt{4}*\sqrt{39}=2\sqrt{39}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12)-2\sqrt{39}}{2*1}=\frac{-12-2\sqrt{39}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+2\sqrt{39}}{2*1}=\frac{-12+2\sqrt{39}}{2}
$