Let us assume she bought, types of the optional features that costs $23.99
and types of the optional features that costs $120.84. Then we will have the expression,
This expression gives us the total cost which is $675.28. This implies that,
We were told that that there were 12 optional features. That is,
Make the subject in equation --(2).
Put equation (3) in equation (1).
Expand the bracket to obtain
Group like terms,
Simplify
Solve for x,
Put in equation (3) to find .
Therefore she bought types of the optional features that costs $23.99
and types of the optional features that costs $120.84.