(n+9)(n-1)=

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

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

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

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

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

Combine like terms: 9n + -1n = 8n
(-9 + 8n + n2) = 0

Solving
-9 + 8n + n2 = 0

Solving for variable 'n'.

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

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

Simplifying
-9 + -1n = 0

Solving
-9 + -1n = 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 + -1n = 0 + 9

Combine like terms: -9 + 9 = 0
0 + -1n = 0 + 9
-1n = 0 + 9

Combine like terms: 0 + 9 = 9
-1n = 9

Divide each side by '-1'.
n = -9

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