8b^2-40=0

Solution for 8b^2-40=0 equation:

8b^2-40=0

a = 8; b = 0; c = -40;
Δ = b2-4ac
Δ = 02-4·8·(-40)
Δ = 1280
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:

$\sqrt{\Delta}=\sqrt{1280}=\sqrt{256*5}=\sqrt{256}*\sqrt{5}=16\sqrt{5}$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-16\sqrt{5}}{2*8}=\frac{0-16\sqrt{5}}{16}
=-\frac{16\sqrt{5}}{16}
=-\sqrt{5}
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+16\sqrt{5}}{2*8}=\frac{0+16\sqrt{5}}{16}
=\frac{16\sqrt{5}}{16}
=\sqrt{5}
$