3(n+2)+2n=21

Solution for 3(n+2)+2n=21 equation:

Simplifying
3(n + 2) + 2n = 21

Reorder the terms:
3(2 + n) + 2n = 21
(2 * 3 + n * 3) + 2n = 21
(6 + 3n) + 2n = 21

Combine like terms: 3n + 2n = 5n
6 + 5n = 21

Solving
6 + 5n = 21

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 + 5n = 21 + -6

Combine like terms: 6 + -6 = 0
0 + 5n = 21 + -6
5n = 21 + -6

Combine like terms: 21 + -6 = 15
5n = 15

Divide each side by '5'.
n = 3

Simplifying
n = 3