Final answer:
To write a compound inequality for the variable x that is represented by a number line extended from -6 to _____, use the form a ≤ x ≤ b, where 'a' is the lower bound and 'b' is the upper bound of x.
Step-by-step explanation:
To write a compound inequality for the variable x that is represented by a number line extended from -6 to the given value, we need to determine the value that extends the number line.
The compound inequality will be written in the form a ≤ x ≤ b, where 'a' is the lower bound and 'b' is the upper bound of x.
For example, if the number line is extended to 10, then the compound inequality would be -6 ≤ x ≤ 10.