Let variable x represent the number of $11.50 CDs
If you buy a total of 12 discs, the number of $7.50 CDs would be ( 12-x).
Total amount spent = $106
Therefore, 11.50x + 7.50(12-x) = $106
Next, open the parentheses and solve for x;
11.50x + 90 -7.50x = 106
11.50x-7.50x = 106-90
4x = 16
divide both sides by 4 to solve for x.
Since we let variable x to represent the number of $11.50 CDs, it means that you bought 4 of them.
is only a line? i think so
$450 i think. hope this ☺