Jerilyn has a coupon and a discount coupon for her favorite store.

Let be the total cost of the items that Jerilyn purchased, excluding discounts.

If she uses the coupon, the cost will be .

If she uses the coupon, the cost will be .

Assume the inequality as .

                               (Original inequality)

     (Subtract from each side)

                                  (Apply additive inverse property: )

                  (Add to each side)

                                        (Apply additive inverse property: )

                                (Divide each side by )

                                           (Cancel common terms)

So, when the total cost of the items purchased is less than , it is best to use the coupon.

The discount is best when the purchase is more than .

The coupon is best when the total cost of the items purchased is less than .

The discount is best when the purchase is more than .