Step 1: expand the parentheses by distributing what's outside:
-12x-9+24x+4=43.
Step 2: group like terms:
12x-5=43.
Step 3: add 5 to each side:
12x=48.
Step 4: divide each side by 12:
x=4 is the solution.
If you're able to, combine steps 1 and 2 and then combine steps 3 and 4.