-5x^2+50x-105=0

Solution for -5x^2+50x-105=0 equation:

-5x^2+50x-105=0

a = -5; b = 50; c = -105;
Δ = b2-4ac
Δ = 502-4·(-5)·(-105)
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(50)-20}{2*-5}=\frac{-70}{-10}
=+7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(50)+20}{2*-5}=\frac{-30}{-10}
=+3
$