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

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

Simplifying
3(a + 3b) + -1(a + 2b) = 0
(a * 3 + 3b * 3) + -1(a + 2b) = 0
(3a + 9b) + -1(a + 2b) = 0
3a + 9b + (a * -1 + 2b * -1) = 0
3a + 9b + (-1a + -2b) = 0

Reorder the terms:
3a + -1a + 9b + -2b = 0

Combine like terms: 3a + -1a = 2a
2a + 9b + -2b = 0

Combine like terms: 9b + -2b = 7b
2a + 7b = 0

Solving
2a + 7b = 0

Solving for variable 'a'.

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

Add '-7b' to each side of the equation.
2a + 7b + -7b = 0 + -7b

Combine like terms: 7b + -7b = 0
2a + 0 = 0 + -7b
2a = 0 + -7b
Remove the zero:
2a = -7b

Divide each side by '2'.
a = -3.5b

Simplifying
a = -3.5b