25c=-10c^2

Solution for 25c=-10c^2 equation:

25c=-10c^2

We move all terms to the left:

25c-(-10c^2)=0

We get rid of parentheses

10c^2+25c=0

a = 10; b = 25; c = 0;
Δ = b2-4ac
Δ = 252-4·10·0
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(25)-25}{2*10}=\frac{-50}{20}
=-2+1/2
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(25)+25}{2*10}=\frac{0}{20}
=0
$