12+3(a+2b)-2a-3b-9+b=

Solution for 12+3(a+2b)-2a-3b-9+b= equation:

Simplifying
12 + 3(a + 2b) + -2a + -3b + -9 + b = 0
12 + (a * 3 + 2b * 3) + -2a + -3b + -9 + b = 0
12 + (3a + 6b) + -2a + -3b + -9 + b = 0

Reorder the terms:
12 + -9 + 3a + -2a + 6b + -3b + b = 0

Combine like terms: 12 + -9 = 3
3 + 3a + -2a + 6b + -3b + b = 0

Combine like terms: 3a + -2a = 1a
3 + 1a + 6b + -3b + b = 0

Combine like terms: 6b + -3b = 3b
3 + 1a + 3b + b = 0

Combine like terms: 3b + b = 4b
3 + 1a + 4b = 0

Solving
3 + 1a + 4b = 0

Solving for variable 'a'.

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

Add '-3' to each side of the equation.
3 + 1a + -3 + 4b = 0 + -3

Reorder the terms:
3 + -3 + 1a + 4b = 0 + -3

Combine like terms: 3 + -3 = 0
0 + 1a + 4b = 0 + -3
1a + 4b = 0 + -3

Combine like terms: 0 + -3 = -3
1a + 4b = -3

Add '-4b' to each side of the equation.
1a + 4b + -4b = -3 + -4b

Combine like terms: 4b + -4b = 0
1a + 0 = -3 + -4b
1a = -3 + -4b

Divide each side by '1'.
a = -3 + -4b

Simplifying
a = -3 + -4b