Find the real roots of
\[(x - 7)(x - 3)(x + 1)(x + 5) = 1680.\]
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Find the real roots of
\[(x - 7)(x - 3)(x + 1)(x + 5) = 1680.\]
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
9,-7
Find the real roots of
\[(x - 7)(x - 3)(x + 1)(x + 5) = 1680.\]
train