At the electronics store you have a coupon for 20% off up to 2 cds you buy for cds with the original cost of $10.99 each the sales tax is 5% what is the total cost of your purchase

  $41.54

Step-by-step explanation:

The price of 2 CDs is ...

  $10.99 × 2 = $21.98

The discount on this price is ...

  20% × $21.98 = $4.40

So, the total price before tax is ...

  2 discounted CDs + 2 regular price CDs =

  $21.98 - 4.40 + 21.98 = $39.56

Then the tax is ...

  5% × $39.56 = $1.98

so the total cost of the purchase is ...

  price before tax + tax =

  $39.56 + 1.98 = $41.54

Alternate solution

Alternatively, you can recognize that the number of discounted CDs is the same as the number of CDs not discounted, so the overall price is the same as it would be with half the discount (that is, 4×10.99 less 10%). The added tax multiplies the price by 1.05, so the overall price is ...

  4 × 0.90 × 10.99 × 1.05 = 3.78 × 10.99 = 41.54

step-by-step explanation:

to find if any function is an inverse of the other, put the first equation in as x in the next one. then simplify and solve. if at the end you get the statement y = x, then it is an inverse. if you get anything else, it is not.