5x2=-15x=0

Solution for 5x2=-15x=0 equation:

5x^2=-15x=0

We move all terms to the left:

5x^2-(-15x)=0

We get rid of parentheses

5x^2+15x=0

a = 5; b = 15; c = 0;
Δ = b2-4ac
Δ = 152-4·5·0
Δ = 225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{225}=15$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-15}{2*5}=\frac{-30}{10}
=-3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+15}{2*5}=\frac{0}{10}
=0
$