6=12+3(m+3)

Solution for 6=12+3(m+3) equation:

Simplifying
6 = 12 + 3(m + 3)

Reorder the terms:
6 = 12 + 3(3 + m)
6 = 12 + (3 * 3 + m * 3)
6 = 12 + (9 + 3m)

Combine like terms: 12 + 9 = 21
6 = 21 + 3m

Solving
6 = 21 + 3m

Solving for variable 'm'.

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

Add '-3m' to each side of the equation.
6 + -3m = 21 + 3m + -3m

Combine like terms: 3m + -3m = 0
6 + -3m = 21 + 0
6 + -3m = 21

Add '-6' to each side of the equation.
6 + -6 + -3m = 21 + -6

Combine like terms: 6 + -6 = 0
0 + -3m = 21 + -6
-3m = 21 + -6

Combine like terms: 21 + -6 = 15
-3m = 15

Divide each side by '-3'.
m = -5

Simplifying
m = -5