5-b^2=10b

Solution for 5-b^2=10b equation:

5-b^2=10b

We move all terms to the left:

5-b^2-(10b)=0

We add all the numbers together, and all the variables

-1b^2-10b+5=0

a = -1; b = -10; c = +5;
Δ = b2-4ac
Δ = -102-4·(-1)·5
Δ = 120
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:

$\sqrt{\Delta}=\sqrt{120}=\sqrt{4*30}=\sqrt{4}*\sqrt{30}=2\sqrt{30}$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-10)-2\sqrt{30}}{2*-1}=\frac{10-2\sqrt{30}}{-2}
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-10)+2\sqrt{30}}{2*-1}=\frac{10+2\sqrt{30}}{-2}
$