-5x^2-8=-13

Solution for -5x^2-8=-13 equation:

-5x^2-8=-13

We move all terms to the left:

-5x^2-8-(-13)=0

We add all the numbers together, and all the variables

-5x^2+5=0

a = -5; b = 0; c = +5;
Δ = b2-4ac
Δ = 02-4·(-5)·5
Δ = 100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{100}=10$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-10}{2*-5}=\frac{-10}{-10}
=1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+10}{2*-5}=\frac{10}{-10}
=-1
$