Question

4. Решите двойное неравенство
- 4<х - 9<5

{x - 9 < 5
{x-9> - 4 ​

Answer 1

$-4<x-9<5\\\\\left \{ {{x-9<5} \atop {x-9>-4}} \right.\\\\\left \{ {{x<5+9} \atop {x>-4+9}} \right. \\\\\left \{ {{x<14} \atop {x>5}} \right. \\\\5<x<14$

x ∈ ( 5 ; 14 )