m^2=-18m-72

Solution for m^2=-18m-72 equation:

m^2=-18m-72

We move all terms to the left:

m^2-(-18m-72)=0

We get rid of parentheses

m^2+18m+72=0

a = 1; b = 18; c = +72;
Δ = b2-4ac
Δ = 182-4·1·72
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-6}{2*1}=\frac{-24}{2}
=-12
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+6}{2*1}=\frac{-12}{2}
=-6
$