n^2+20n-21=0

Solution for n^2+20n-21=0 equation:

Simplifying
n2 + 20n + -21 = 0

Reorder the terms:
-21 + 20n + n2 = 0

Solving
-21 + 20n + n2 = 0

Solving for variable 'n'.

Factor a trinomial.
(-21 + -1n)(1 + -1n) = 0

Subproblem 1
Set the factor '(-21 + -1n)' equal to zero and attempt to solve:

Simplifying
-21 + -1n = 0

Solving
-21 + -1n = 0

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

Add '21' to each side of the equation.
-21 + 21 + -1n = 0 + 21

Combine like terms: -21 + 21 = 0
0 + -1n = 0 + 21
-1n = 0 + 21

Combine like terms: 0 + 21 = 21
-1n = 21

Divide each side by '-1'.
n = -21

Simplifying
n = -21
Subproblem 2
Set the factor '(1 + -1n)' equal to zero and attempt to solve:

Simplifying
1 + -1n = 0

Solving
1 + -1n = 0

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

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

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

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

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

Simplifying
n = 1
Solution
n = {-21, 1}