-4m^2-20m+24=0

Solution for -4m^2-20m+24=0 equation:

-4m^2-20m+24=0

a = -4; b = -20; c = +24;
Δ = b2-4ac
Δ = -202-4·(-4)·24
Δ = 784
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{784}=28$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-20)-28}{2*-4}=\frac{-8}{-8}
=1
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+28}{2*-4}=\frac{48}{-8}
=-6
$