-2(a+3)-4a=12

Solution for -2(a+3)-4a=12 equation:

Simplifying
-2(a + 3) + -4a = 12

Reorder the terms:
-2(3 + a) + -4a = 12
(3 * -2 + a * -2) + -4a = 12
(-6 + -2a) + -4a = 12

Combine like terms: -2a + -4a = -6a
-6 + -6a = 12

Solving
-6 + -6a = 12

Solving for variable 'a'.

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

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

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

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

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

Simplifying
a = -3