$\"\"$

Cost of each CD $\"\"$

Cost for 3 CD’s $\"\"$

Cost of each digital song $\"\"$

Cost for 2 digital songs $\"\"$

$\"\"$

Thus, the algebraic expression for current situation is

“ $\"\"$ ”

The algebraic expression is $\"\"$ .

$\"\"$

$\"\"$ (Multiply: $\"\"$ )

$\"\"$ (Add: $\"\"$ )

$\"\"$

The total cost is $\"\"$