9x^2-9=279

Solution for 9x^2-9=279 equation:

9x^2-9=279

We move all terms to the left:

9x^2-9-(279)=0

We add all the numbers together, and all the variables

9x^2-288=0

a = 9; b = 0; c = -288;
Δ = b2-4ac
Δ = 02-4·9·(-288)
Δ = 10368
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:

$\sqrt{\Delta}=\sqrt{10368}=\sqrt{5184*2}=\sqrt{5184}*\sqrt{2}=72\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-72\sqrt{2}}{2*9}=\frac{0-72\sqrt{2}}{18}
=-\frac{72\sqrt{2}}{18}
=-4\sqrt{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+72\sqrt{2}}{2*9}=\frac{0+72\sqrt{2}}{18}
=\frac{72\sqrt{2}}{18}
=4\sqrt{2}
$