Final answer:
The buyer lost the discount of $168.
Step-by-step explanation:
The buyer lost the discount of $168.
To calculate the discount, we first need to find the amount the buyer could have saved if they took advantage of the cash discount. The discount is calculated as the product of the invoice amount and the discount rate. In this case, the invoice amount is $8,400 and the discount rate is 2%, which is equivalent to 0.02 as a decimal. So the discount amount would be $8,400 * 0.02 = $168.