4a^2-18=12a

Solution for 4a^2-18=12a equation:

4a^2-18=12a

We move all terms to the left:

4a^2-18-(12a)=0

a = 4; b = -12; c = -18;
Δ = b2-4ac
Δ = -122-4·4·(-18)
Δ = 432
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{432}=\sqrt{144*3}=\sqrt{144}*\sqrt{3}=12\sqrt{3}$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-12\sqrt{3}}{2*4}=\frac{12-12\sqrt{3}}{8}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+12\sqrt{3}}{2*4}=\frac{12+12\sqrt{3}}{8}
$