30r^2=15

Solution for 30r^2=15 equation:

30r^2=15

We move all terms to the left:

30r^2-(15)=0

a = 30; b = 0; c = -15;
Δ = b2-4ac
Δ = 02-4·30·(-15)
Δ = 1800
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1800}=\sqrt{900*2}=\sqrt{900}*\sqrt{2}=30\sqrt{2}$
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-30\sqrt{2}}{2*30}=\frac{0-30\sqrt{2}}{60}
=-\frac{30\sqrt{2}}{60}
=-\frac{\sqrt{2}}{2}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+30\sqrt{2}}{2*30}=\frac{0+30\sqrt{2}}{60}
=\frac{30\sqrt{2}}{60}
=\frac{\sqrt{2}}{2}
$