81x2+99x+28=0

Solution for 81x2+99x+28=0 equation:

81x^2+99x+28=0

a = 81; b = 99; c = +28;
Δ = b2-4ac
Δ = 992-4·81·28
Δ = 729
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{729}=27$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(99)-27}{2*81}=\frac{-126}{162}
=-7/9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(99)+27}{2*81}=\frac{-72}{162}
=-4/9
$