81x^2+90x+9=0

Solution for 81x^2+90x+9=0 equation:

81x^2+90x+9=0

a = 81; b = 90; c = +9;
Δ = b2-4ac
Δ = 902-4·81·9
Δ = 5184
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5184}=72$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(90)-72}{2*81}=\frac{-162}{162}
=-1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(90)+72}{2*81}=\frac{-18}{162}
=-1/9
$