5r^2=-25r

Solution for 5r^2=-25r equation:

5r^2=-25r

We move all terms to the left:

5r^2-(-25r)=0

We get rid of parentheses

5r^2+25r=0

a = 5; b = 25; c = 0;
Δ = b2-4ac
Δ = 252-4·5·0
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(25)-25}{2*5}=\frac{-50}{10}
=-5
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(25)+25}{2*5}=\frac{0}{10}
=0
$