4x^2+12=135

Solution for 4x^2+12=135 equation:

4x^2+12=135

We move all terms to the left:

4x^2+12-(135)=0

We add all the numbers together, and all the variables

4x^2-123=0

a = 4; b = 0; c = -123;
Δ = b2-4ac
Δ = 02-4·4·(-123)
Δ = 1968
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:

$\sqrt{\Delta}=\sqrt{1968}=\sqrt{16*123}=\sqrt{16}*\sqrt{123}=4\sqrt{123}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{123}}{2*4}=\frac{0-4\sqrt{123}}{8}
=-\frac{4\sqrt{123}}{8}
=-\frac{\sqrt{123}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{123}}{2*4}=\frac{0+4\sqrt{123}}{8}
=\frac{4\sqrt{123}}{8}
=\frac{\sqrt{123}}{2}
$