Add. Simplify the answer

Answer:
[tex]4g^{2}h-12gh^{2}-9gh[/tex]
Copy and paste version:
4g^2h-12gh^2-9gh
Step-by-step explanation:
[tex](4g^{2}h-gh-9gh^{2})+(8gh-3gh^{2})=\\4g^{2}h-gh-9gh^{2}+8gh-3gh^{2}=\\4g^{2}h-9gh-12gh^{2}=\\4g^{2}h-12gh^{2}-9gh[/tex]