2x^2+2(x^2)=240

Solution for 2x^2+2(x^2)=240 equation:

2x^2+2(x^2)=240

We move all terms to the left:

2x^2+2(x^2)-(240)=0

We add all the numbers together, and all the variables

4x^2-240=0

a = 4; b = 0; c = -240;
Δ = b2-4ac
Δ = 02-4·4·(-240)
Δ = 3840
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:

$\sqrt{\Delta}=\sqrt{3840}=\sqrt{256*15}=\sqrt{256}*\sqrt{15}=16\sqrt{15}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-16\sqrt{15}}{2*4}=\frac{0-16\sqrt{15}}{8}
=-\frac{16\sqrt{15}}{8}
=-2\sqrt{15}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+16\sqrt{15}}{2*4}=\frac{0+16\sqrt{15}}{8}
=\frac{16\sqrt{15}}{8}
=2\sqrt{15}
$