A jeweler had a fixed amount of gold to make bracelets and necklaces. The amount of gold in each bracelet is 8 grams and the amount of gold in each necklace is 24 grams. The jeweler made a total of 13 bracelets and necklaces using 168 grams of gold. Write a system of equations that could be used to determine the number of bracelets made and the number of necklaces made. Define the variables that you use to write the system.