6+3(a+b)=9

Solution for 6+3(a+b)=9 equation:

Simplifying
6 + 3(a + b) = 9
6 + (a * 3 + b * 3) = 9
6 + (3a + 3b) = 9

Solving
6 + 3a + 3b = 9

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 + 3a + -6 + 3b = 9 + -6

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

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

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

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

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

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

Simplifying
a = 1 + -1b