8-9n^2=-721

Solution for 8-9n^2=-721 equation:

8-9n^2=-721

We move all terms to the left:

8-9n^2-(-721)=0

We add all the numbers together, and all the variables

-9n^2+729=0

a = -9; b = 0; c = +729;
Δ = b2-4ac
Δ = 02-4·(-9)·729
Δ = 26244
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{26244}=162$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-162}{2*-9}=\frac{-162}{-18}
=+9
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+162}{2*-9}=\frac{162}{-18}
=-9
$