3. For what values of the parameter $a$ does the inequality $\left(a^{2}-6 a-7\right)|x|+(-a-19) \sqrt{x^{2}-9}>0$ have no solutions? Write the answer as an interval. If the set of answers consists of several intervals, list them separated by a semicolon.
Answer: $[-1 ; 7]$

## Examples of answer notation:

$[1 ; 2)$

$[0 ; 1] ;(2 ; 3)$

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