13x2+5x2=36

Solution for 13x2+5x2=36 equation:

13x^2+5x^2=36

We move all terms to the left:

13x^2+5x^2-(36)=0

We add all the numbers together, and all the variables

18x^2-36=0

a = 18; b = 0; c = -36;
Δ = b2-4ac
Δ = 02-4·18·(-36)
Δ = 2592
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:

$\sqrt{\Delta}=\sqrt{2592}=\sqrt{1296*2}=\sqrt{1296}*\sqrt{2}=36\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-36\sqrt{2}}{2*18}=\frac{0-36\sqrt{2}}{36}
=-\frac{36\sqrt{2}}{36}
=-\sqrt{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+36\sqrt{2}}{2*18}=\frac{0+36\sqrt{2}}{36}
=\frac{36\sqrt{2}}{36}
=\sqrt{2}
$