(n+1)(n+9)=0

Solution for (n+1)(n+9)=0 equation:

Simplifying
(n + 1)(n + 9) = 0

Reorder the terms:
(1 + n)(n + 9) = 0

Reorder the terms:
(1 + n)(9 + n) = 0

Multiply (1 + n) * (9 + n)
(1(9 + n) + n(9 + n)) = 0
((9 * 1 + n * 1) + n(9 + n)) = 0
((9 + 1n) + n(9 + n)) = 0
(9 + 1n + (9 * n + n * n)) = 0
(9 + 1n + (9n + n2)) = 0

Combine like terms: 1n + 9n = 10n
(9 + 10n + n2) = 0

Solving
9 + 10n + n2 = 0

Solving for variable 'n'.

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

Subproblem 1
Set the factor '(9 + n)' equal to zero and attempt to solve:

Simplifying
9 + n = 0

Solving
9 + n = 0

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

Add '-9' to each side of the equation.
9 + -9 + n = 0 + -9

Combine like terms: 9 + -9 = 0
0 + n = 0 + -9
n = 0 + -9

Combine like terms: 0 + -9 = -9
n = -9

Simplifying
n = -9
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 = {-9, -1}