3(1+n)+3(n+1)=-12

Solution for 3(1+n)+3(n+1)=-12 equation:

Simplifying
3(1 + n) + 3(n + 1) = -12
(1 * 3 + n * 3) + 3(n + 1) = -12
(3 + 3n) + 3(n + 1) = -12

Reorder the terms:
3 + 3n + 3(1 + n) = -12
3 + 3n + (1 * 3 + n * 3) = -12
3 + 3n + (3 + 3n) = -12

Reorder the terms:
3 + 3 + 3n + 3n = -12

Combine like terms: 3 + 3 = 6
6 + 3n + 3n = -12

Combine like terms: 3n + 3n = 6n
6 + 6n = -12

Solving
6 + 6n = -12

Solving for variable 'n'.

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

Add '-6' to each side of the equation.
6 + -6 + 6n = -12 + -6

Combine like terms: 6 + -6 = 0
0 + 6n = -12 + -6
6n = -12 + -6

Combine like terms: -12 + -6 = -18
6n = -18

Divide each side by '6'.
n = -3

Simplifying
n = -3