20b^2-15=0

Solution for 20b^2-15=0 equation:

20b^2-15=0

a = 20; b = 0; c = -15;
Δ = b2-4ac
Δ = 02-4·20·(-15)
Δ = 1200
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1200}=\sqrt{400*3}=\sqrt{400}*\sqrt{3}=20\sqrt{3}$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-20\sqrt{3}}{2*20}=\frac{0-20\sqrt{3}}{40}
=-\frac{20\sqrt{3}}{40}
=-\frac{\sqrt{3}}{2}
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+20\sqrt{3}}{2*20}=\frac{0+20\sqrt{3}}{40}
=\frac{20\sqrt{3}}{40}
=\frac{\sqrt{3}}{2}
$