5x^2-8=172

Solution for 5x^2-8=172 equation:

5x^2-8=172

We move all terms to the left:

5x^2-8-(172)=0

We add all the numbers together, and all the variables

5x^2-180=0

a = 5; b = 0; c = -180;
Δ = b2-4ac
Δ = 02-4·5·(-180)
Δ = 3600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3600}=60$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-60}{2*5}=\frac{-60}{10}
=-6
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+60}{2*5}=\frac{60}{10}
=6
$