5b=-10b^2

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

5b=-10b^2

We move all terms to the left:

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

We get rid of parentheses

10b^2+5b=0

a = 10; b = 5; c = 0;
Δ = b2-4ac
Δ = 52-4·10·0
Δ = 25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{25}=5$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-5}{2*10}=\frac{-10}{20}
=-1/2
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+5}{2*10}=\frac{0}{20}
=0
$