5d(8d+9)=0

Solution for 5d(8d+9)=0 equation:

5d(8d+9)=0

We multiply parentheses

40d^2+45d=0

a = 40; b = 45; c = 0;
Δ = b2-4ac
Δ = 452-4·40·0
Δ = 2025
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2025}=45$
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(45)-45}{2*40}=\frac{-90}{80}
=-1+1/8
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(45)+45}{2*40}=\frac{0}{80}
=0
$