4x^2+9x^2=144

Solution for 4x^2+9x^2=144 equation:

4x^2+9x^2=144

We move all terms to the left:

4x^2+9x^2-(144)=0

We add all the numbers together, and all the variables

13x^2-144=0

a = 13; b = 0; c = -144;
Δ = b2-4ac
Δ = 02-4·13·(-144)
Δ = 7488
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:

$\sqrt{\Delta}=\sqrt{7488}=\sqrt{576*13}=\sqrt{576}*\sqrt{13}=24\sqrt{13}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-24\sqrt{13}}{2*13}=\frac{0-24\sqrt{13}}{26}
=-\frac{24\sqrt{13}}{26}
=-\frac{12\sqrt{13}}{13}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+24\sqrt{13}}{2*13}=\frac{0+24\sqrt{13}}{26}
=\frac{24\sqrt{13}}{26}
=\frac{12\sqrt{13}}{13}
$