Question 21134
You cannot solve this equation until you get all the variables on the same side.


12-2a = -5a-9  First, add 2a to each side of the equation.


You get:  12-2a+2a = -5a-9+2a
Simplified it becomes:  12 = -3a-9  Now, add 9 to each side.
You get:  12+9 = -3a-9+9
Simplified it becomes:  21 = -3a
21/-3 = a

-7 = a

You can check the correctness of this answer by substituting -7 for a in the original equation.