The function $f(x)$ satisfies
\[f(x) + 2f(1 - x) = 3x^2\]for all real numbers $x.$  Find $f(3).$
<|im_start|>system
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<|im_start|>user
The function $f(x)$ satisfies
\[f(x) + 2f(1 - x) = 3x^2\]for all real numbers $x.$  Find $f(3).$
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
-1
The function $f(x)$ satisfies
\[f(x) + 2f(1 - x) = 3x^2\]for all real numbers $x.$  Find $f(3).$
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