n+(n+6)=90

Solution for n+(n+6)=90 equation:

Simplifying
n + (n + 6) = 90

Reorder the terms:
n + (6 + n) = 90

Remove parenthesis around (6 + n)
n + 6 + n = 90

Reorder the terms:
6 + n + n = 90

Combine like terms: n + n = 2n
6 + 2n = 90

Solving
6 + 2n = 90

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 + 2n = 90 + -6

Combine like terms: 6 + -6 = 0
0 + 2n = 90 + -6
2n = 90 + -6

Combine like terms: 90 + -6 = 84
2n = 84

Divide each side by '2'.
n = 42

Simplifying
n = 42