The inequality $x < -4$ represents all values of $x$ that are less than -4. In interval notation, this is written as:

$(-\infty, -4)$

This means that $x$ can take any value from negative infinity up to, but not including, -4.

Would you like further details on interval notation or have any questions?

Here are 5 related questions:

1. How would you express $x \leq -4$ in interval notation?
2. What is the interval notation for $x > 5$?
3. Can you express $-2 \leq x < 3$ using interval notation?
4. How do you combine intervals for inequalities like $x < -4$ or $x > 2$?
5. What is the interval notation for $-1 < x \leq 4$?

Tip: Always remember that round brackets $()$ indicate that an endpoint is not included, and square brackets $[]$ indicate that it is included.