Express the inequality x≤-0.12 using interval notation.

(-∞, - 0.12]

Step-by-step explanation:

Imagine x ≤ - 0.12 on a number line. It's a closed dot at - 0.12 and then an arrow shooting infinitely towards the left.

The lower bound of this set of values is - ∞ because it just keeps going; x can be anything less than - 0.12, no matter how negative it is. The parenthesis is used (not the bracket) because the parenthesis is always used with an infinite limit.

The upper bound of this set of values is - 0.12 because x can't be any greater than - 0.12. The bracket is used (not the parenthesis) because x can be less than or equal to - 0.12. When there is a line underneath, use the bracket.