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

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

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

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

Remove parenthesis around (-1 + n)
n + -1 + n + (n + -2) = 0

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

Remove parenthesis around (-2 + n)
n + -1 + n + -2 + n = 0

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

Combine like terms: -1 + -2 = -3
-3 + n + n + n = 0

Combine like terms: n + n = 2n
-3 + 2n + n = 0

Combine like terms: 2n + n = 3n
-3 + 3n = 0

Solving
-3 + 3n = 0

Solving for variable 'n'.

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

Add '3' to each side of the equation.
-3 + 3 + 3n = 0 + 3

Combine like terms: -3 + 3 = 0
0 + 3n = 0 + 3
3n = 0 + 3

Combine like terms: 0 + 3 = 3
3n = 3

Divide each side by '3'.
n = 1

Simplifying
n = 1