72x^2=15

Solution for 72x^2=15 equation:

72x^2=15

We move all terms to the left:

72x^2-(15)=0

a = 72; b = 0; c = -15;
Δ = b2-4ac
Δ = 02-4·72·(-15)
Δ = 4320
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:

$\sqrt{\Delta}=\sqrt{4320}=\sqrt{144*30}=\sqrt{144}*\sqrt{30}=12\sqrt{30}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-12\sqrt{30}}{2*72}=\frac{0-12\sqrt{30}}{144}
=-\frac{12\sqrt{30}}{144}
=-\frac{\sqrt{30}}{12}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+12\sqrt{30}}{2*72}=\frac{0+12\sqrt{30}}{144}
=\frac{12\sqrt{30}}{144}
=\frac{\sqrt{30}}{12}
$