-13m-40-m^2=0

Solution for -13m-40-m^2=0 equation:

-13m-40-m^2=0

We add all the numbers together, and all the variables

-1m^2-13m-40=0

a = -1; b = -13; c = -40;
Δ = b2-4ac
Δ = -132-4·(-1)·(-40)
Δ = 9
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{9}=3$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-13)-3}{2*-1}=\frac{10}{-2}
=-5
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-13)+3}{2*-1}=\frac{16}{-2}
=-8
$