3a+12a+6=-3

Solution for 3a+12a+6=-3 equation:

Simplifying
3a + 12a + 6 = -3

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

Combine like terms: 3a + 12a = 15a
6 + 15a = -3

Solving
6 + 15a = -3

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 + 15a = -3 + -6

Combine like terms: 6 + -6 = 0
0 + 15a = -3 + -6
15a = -3 + -6

Combine like terms: -3 + -6 = -9
15a = -9

Divide each side by '15'.
a = -0.6

Simplifying
a = -0.6