1200=3x^2

Solution for 1200=3x^2 equation:

1200=3x^2

We move all terms to the left:

1200-(3x^2)=0

a = -3; b = 0; c = +1200;
Δ = b2-4ac
Δ = 02-4·(-3)·1200
Δ = 14400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{14400}=120$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-120}{2*-3}=\frac{-120}{-6}
=+20
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+120}{2*-3}=\frac{120}{-6}
=-20
$