-5x2+50x-120=0

Solution for -5x2+50x-120=0 equation:

-5x^2+50x-120=0

a = -5; b = 50; c = -120;
Δ = b2-4ac
Δ = 502-4·(-5)·(-120)
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{-(50)-10}{2*-5}=\frac{-60}{-10}
=+6
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(50)+10}{2*-5}=\frac{-40}{-10}
=+4
$