Answer:
$8
Step-by-step explanation:
20% (= 0.20) is deducted from $40.40 * 0.20 = $8.
When multiplying numbers a negative number will make a positive into a negative. Yet if multiplied again by another negative it will cancel out or make it positive again. Seeing as answer c has only one negative it's the correct answer.
The answer to your question is 4
This is called a double equation. If you solve for X, you would get 'any whole number.'