[ -4, 5 ]
notice the brackets, as opposed to parentheses.
the brackets mean, -4 is a bound and it is included in the range, and 5 is the other bound and 5 is also included in the range too.
so, whatever number "x" is, we know that is between -4 and 5, so it could be -3, -2, 1, 4 or such.
keeping in mind that, for the negative side of the numbers, the closer to 0, the greater the number, therefore, -4 is greater than -5 and is also greater than -1,000,000, because -4 is closer to 0 than those two.
so, "x" is greater than -4, and includes it, but is also less than 5, but it can be 5 too.
check the picture below.