3d(d-5)=0

Solution for 3d(d-5)=0 equation:

3d(d-5)=0

We multiply parentheses

3d^2-15d=0

a = 3; b = -15; c = 0;
Δ = b2-4ac
Δ = -152-4·3·0
Δ = 225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{225}=15$
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-15)-15}{2*3}=\frac{0}{6}
=0
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+15}{2*3}=\frac{30}{6}
=5
$