A^2-19A-20=0

Solution for A^2-19A-20=0 equation:

Simplifying
A2 + -19A + -20 = 0

Reorder the terms:
-20 + -19A + A2 = 0

Solving
-20 + -19A + A2 = 0

Solving for variable 'A'.

Factor a trinomial.
(-1 + -1A)(20 + -1A) = 0

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

Simplifying
-1 + -1A = 0

Solving
-1 + -1A = 0

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

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

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

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

Divide each side by '-1'.
A = -1

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

Simplifying
20 + -1A = 0

Solving
20 + -1A = 0

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

Add '-20' to each side of the equation.
20 + -20 + -1A = 0 + -20

Combine like terms: 20 + -20 = 0
0 + -1A = 0 + -20
-1A = 0 + -20

Combine like terms: 0 + -20 = -20
-1A = -20

Divide each side by '-1'.
A = 20

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