x = 4
This is shown through a set of steps:
First, distribute:
-12x - 9 + 24x + 4 = 43
Note that the three turned into a negative, this is because the number outside of the parenthesis is also negative.
Then, combine like terms:
12x - 5 = 43
Then proceed to solve the equation:
12 x = 48
x = 4
Hope this helps!