5y(2y+5)=0

Solution for 5y(2y+5)=0 equation:

5y(2y+5)=0

We multiply parentheses

10y^2+25y=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:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

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