m^2+21m+20=0

Solution for m^2+21m+20=0 equation:

Simplifying
m2 + 21m + 20 = 0

Reorder the terms:
20 + 21m + m2 = 0

Solving
20 + 21m + m2 = 0

Solving for variable 'm'.

Factor a trinomial.
(20 + m)(1 + m) = 0

Subproblem 1
Set the factor '(20 + m)' equal to zero and attempt to solve:

Simplifying
20 + m = 0

Solving
20 + m = 0

Move all terms containing m to the left, all other terms to the right.

Add '-20' to each side of the equation.
20 + -20 + m = 0 + -20

Combine like terms: 20 + -20 = 0
0 + m = 0 + -20
m = 0 + -20

Combine like terms: 0 + -20 = -20
m = -20

Simplifying
m = -20
Subproblem 2
Set the factor '(1 + m)' equal to zero and attempt to solve:

Simplifying
1 + m = 0

Solving
1 + m = 0

Move all terms containing m to the left, all other terms to the right.

Add '-1' to each side of the equation.
1 + -1 + m = 0 + -1

Combine like terms: 1 + -1 = 0
0 + m = 0 + -1
m = 0 + -1

Combine like terms: 0 + -1 = -1
m = -1

Simplifying
m = -1
Solution
m = {-20, -1}