3(2-4a)-3(a+6)=123

Solution for 3(2-4a)-3(a+6)=123 equation:

Simplifying
3(2 + -4a) + -3(a + 6) = 123
(2 * 3 + -4a * 3) + -3(a + 6) = 123
(6 + -12a) + -3(a + 6) = 123

Reorder the terms:
6 + -12a + -3(6 + a) = 123
6 + -12a + (6 * -3 + a * -3) = 123
6 + -12a + (-18 + -3a) = 123

Reorder the terms:
6 + -18 + -12a + -3a = 123

Combine like terms: 6 + -18 = -12
-12 + -12a + -3a = 123

Combine like terms: -12a + -3a = -15a
-12 + -15a = 123

Solving
-12 + -15a = 123

Solving for variable 'a'.

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

Add '12' to each side of the equation.
-12 + 12 + -15a = 123 + 12

Combine like terms: -12 + 12 = 0
0 + -15a = 123 + 12
-15a = 123 + 12

Combine like terms: 123 + 12 = 135
-15a = 135

Divide each side by '-15'.
a = -9

Simplifying
a = -9