(n+1)(n-2)=0

Solution for (n+1)(n-2)=0 equation:

Simplifying
(n + 1)(n + -2) = 0

Reorder the terms:
(1 + n)(n + -2) = 0

Reorder the terms:
(1 + n)(-2 + n) = 0

Multiply (1 + n) * (-2 + n)
(1(-2 + n) + n(-2 + n)) = 0
((-2 * 1 + n * 1) + n(-2 + n)) = 0
((-2 + 1n) + n(-2 + n)) = 0
(-2 + 1n + (-2 * n + n * n)) = 0
(-2 + 1n + (-2n + n2)) = 0

Combine like terms: 1n + -2n = -1n
(-2 + -1n + n2) = 0

Solving
-2 + -1n + n2 = 0

Solving for variable 'n'.

Factor a trinomial.
(-1 + -1n)(2 + -1n) = 0

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

Simplifying
2 + -1n = 0

Solving
2 + -1n = 0

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

Add '-2' to each side of the equation.
2 + -2 + -1n = 0 + -2

Combine like terms: 2 + -2 = 0
0 + -1n = 0 + -2
-1n = 0 + -2

Combine like terms: 0 + -2 = -2
-1n = -2

Divide each side by '-1'.
n = 2

Simplifying
n = 2
Solution
n = {-1, 2}