I'll give you a hint. You had to used pemdas stands for: p-parenthesis, e-exponents, m-multiply, d-divide, a-add and s-subtracting that came from left to right.
First you had to calculate with parenthesis first.
[tex](15)+(9-3)[/tex]
[tex](15)+6[/tex]
Then you add and subtract from left to right.
[tex]15+6=21[/tex]
[tex]12+21[/tex]
Finally add and subtract from left to right.
[tex]=33[/tex]
Final answer: [tex]\boxed{=33}[/tex]
Hope this helps!
And thank you for posting your question at here on brainly, and have a great day.
-Charlie
