n^2+18n+21=4

Solution for n^2+18n+21=4 equation:

Simplifying
n2 + 18n + 21 = 4

Reorder the terms:
21 + 18n + n2 = 4

Solving
21 + 18n + n2 = 4

Solving for variable 'n'.

Reorder the terms:
21 + -4 + 18n + n2 = 4 + -4

Combine like terms: 21 + -4 = 17
17 + 18n + n2 = 4 + -4

Combine like terms: 4 + -4 = 0
17 + 18n + n2 = 0

Factor a trinomial.
(17 + n)(1 + n) = 0

Subproblem 1
Set the factor '(17 + n)' equal to zero and attempt to solve:

Simplifying
17 + n = 0

Solving
17 + n = 0

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

Add '-17' to each side of the equation.
17 + -17 + n = 0 + -17

Combine like terms: 17 + -17 = 0
0 + n = 0 + -17
n = 0 + -17

Combine like terms: 0 + -17 = -17
n = -17

Simplifying
n = -17
Subproblem 2
Set the factor '(1 + n)' equal to zero and attempt to solve:

Simplifying
1 + n = 0

Solving
1 + n = 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 + n = 0 + -1

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

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

Simplifying
n = -1
Solution
n = {-17, -1}