9x^2-2=718

Solution for 9x^2-2=718 equation:

9x^2-2=718

We move all terms to the left:

9x^2-2-(718)=0

We add all the numbers together, and all the variables

9x^2-720=0

a = 9; b = 0; c = -720;
Δ = b2-4ac
Δ = 02-4·9·(-720)
Δ = 25920
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{25920}=\sqrt{5184*5}=\sqrt{5184}*\sqrt{5}=72\sqrt{5}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-72\sqrt{5}}{2*9}=\frac{0-72\sqrt{5}}{18}
=-\frac{72\sqrt{5}}{18}
=-4\sqrt{5}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+72\sqrt{5}}{2*9}=\frac{0+72\sqrt{5}}{18}
=\frac{72\sqrt{5}}{18}
=4\sqrt{5}
$