-15x^2+150x-240=0

Solution for -15x^2+150x-240=0 equation:

-15x^2+150x-240=0

a = -15; b = 150; c = -240;
Δ = b2-4ac
Δ = 1502-4·(-15)·(-240)
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{-(150)-90}{2*-15}=\frac{-240}{-30}
=+8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(150)+90}{2*-15}=\frac{-60}{-30}
=+2
$