10x^2+91x+9=0

Solution for 10x^2+91x+9=0 equation:

10x^2+91x+9=0

a = 10; b = 91; c = +9;
Δ = b2-4ac
Δ = 912-4·10·9
Δ = 7921
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{7921}=89$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(91)-89}{2*10}=\frac{-180}{20}
=-9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(91)+89}{2*10}=\frac{-2}{20}
=-1/10
$