(3a+6b)-(-3a-6b)=

Solution for (3a+6b)-(-3a-6b)= equation:

Simplifying
(3a + 6b) + -1(-3a + -6b) = 0

Remove parenthesis around (3a + 6b)
3a + 6b + -1(-3a + -6b) = 0
3a + 6b + (-3a * -1 + -6b * -1) = 0
3a + 6b + (3a + 6b) = 0

Reorder the terms:
3a + 3a + 6b + 6b = 0

Combine like terms: 3a + 3a = 6a
6a + 6b + 6b = 0

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

Solving
6a + 12b = 0

Solving for variable 'a'.

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

Add '-12b' to each side of the equation.
6a + 12b + -12b = 0 + -12b

Combine like terms: 12b + -12b = 0
6a + 0 = 0 + -12b
6a = 0 + -12b
Remove the zero:
6a = -12b

Divide each side by '6'.
a = -2b

Simplifying
a = -2b