m2+9m=-2m2

Solution for m2+9m=-2m2 equation:

m2+9m=-2m^2

We move all terms to the left:

m2+9m-(-2m^2)=0

We add all the numbers together, and all the variables

m^2-(-2m^2)+9m=0

We get rid of parentheses

m^2+2m^2+9m=0

We add all the numbers together, and all the variables

3m^2+9m=0

a = 3; b = 9; c = 0;
Δ = b2-4ac
Δ = 92-4·3·0
Δ = 81
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{81}=9$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(9)-9}{2*3}=\frac{-18}{6}
=-3
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+9}{2*3}=\frac{0}{6}
=0
$