X2+12x=72

Solution for X2+12x=72 equation:

X2+12X=72

We move all terms to the left:

X2+12X-(72)=0

We add all the numbers together, and all the variables

X^2+12X-72=0

a = 1; b = 12; c = -72;
Δ = b2-4ac
Δ = 122-4·1·(-72)
Δ = 432
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:

$\sqrt{\Delta}=\sqrt{432}=\sqrt{144*3}=\sqrt{144}*\sqrt{3}=12\sqrt{3}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12)-12\sqrt{3}}{2*1}=\frac{-12-12\sqrt{3}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+12\sqrt{3}}{2*1}=\frac{-12+12\sqrt{3}}{2}
$