X2+x2=126

Solution for X2+x2=126 equation:

X2+X2=126

We move all terms to the left:

X2+X2-(126)=0

We add all the numbers together, and all the variables

2X^2-126=0

a = 2; b = 0; c = -126;
Δ = b2-4ac
Δ = 02-4·2·(-126)
Δ = 1008
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:

$\sqrt{\Delta}=\sqrt{1008}=\sqrt{144*7}=\sqrt{144}*\sqrt{7}=12\sqrt{7}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-12\sqrt{7}}{2*2}=\frac{0-12\sqrt{7}}{4}
=-\frac{12\sqrt{7}}{4}
=-3\sqrt{7}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+12\sqrt{7}}{2*2}=\frac{0+12\sqrt{7}}{4}
=\frac{12\sqrt{7}}{4}
=3\sqrt{7}
$