Final answer:
The correct unsimplified expression for buying 5 face masks with a 30% discount is 5x(1−0.30).
Step-by-step explanation:
The correct unsimplified expression for buying 5 face masks with a 30% discount is option B. 5x(1−0.30).
To determine the final price after the discount, we need to multiply the original price by 1 minus the discount rate. In this case, the original price is 5x and the discount rate is 30%, which can be written as 0.30. So, the expression becomes 5x(1−0.30), which simplifies to 5x(0.70) or 3.5x.
Therefore, the correct unsimplified expression is 5x(1−0.30).