3x^2-9=369

Solution for 3x^2-9=369 equation:

3x^2-9=369

We move all terms to the left:

3x^2-9-(369)=0

We add all the numbers together, and all the variables

3x^2-378=0

a = 3; b = 0; c = -378;
Δ = b2-4ac
Δ = 02-4·3·(-378)
Δ = 4536
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:

$\sqrt{\Delta}=\sqrt{4536}=\sqrt{324*14}=\sqrt{324}*\sqrt{14}=18\sqrt{14}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-18\sqrt{14}}{2*3}=\frac{0-18\sqrt{14}}{6}
=-\frac{18\sqrt{14}}{6}
=-3\sqrt{14}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+18\sqrt{14}}{2*3}=\frac{0+18\sqrt{14}}{6}
=\frac{18\sqrt{14}}{6}
=3\sqrt{14}
$