-15x^2+135=0

Solution for -15x^2+135=0 equation:

-15x^2+135=0

a = -15; b = 0; c = +135;
Δ = b2-4ac
Δ = 02-4·(-15)·135
Δ = 8100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{8100}=90$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-90}{2*-15}=\frac{-90}{-30}
=+3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+90}{2*-15}=\frac{90}{-30}
=-3
$