Answer:
[tex]\boxed{\sf 1.6 < x < 9.6}[/tex]
Step-by-step explanation:
According to the triangle inequality theorem, any triangle side is always shorter than the sum of the other two sides.
Therefore the third side must be less than 4.0 + 5.6 = 9.6.
The third side must likewise be bigger than the difference between the previous two sides, according to the same theory.
Therefore the third side must be larger than 5.6 - 4.0 = 1.6.
So, 1.6 < x < 9.6
