2q(9-q)=0

Solution for 2q(9-q)=0 equation:

2q(9-q)=0

We add all the numbers together, and all the variables

2q(-1q+9)=0

We multiply parentheses

-2q^2+18q=0

a = -2; b = 18; c = 0;
Δ = b2-4ac
Δ = 182-4·(-2)·0
Δ = 324
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$q_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$q_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{324}=18$
$q_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-18}{2*-2}=\frac{-36}{-4}
=+9
$
$q_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+18}{2*-2}=\frac{0}{-4}
=0
$