9x(9x-10)=0

Solution for 9x(9x-10)=0 equation:

9x(9x-10)=0

We multiply parentheses

81x^2-90x=0

a = 81; b = -90; c = 0;
Δ = b2-4ac
Δ = -902-4·81·0
Δ = 8100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{8100}=90$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-90)-90}{2*81}=\frac{0}{162}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-90)+90}{2*81}=\frac{180}{162}
=1+1/9
$