Answer:
Step-by-step explanation: After purchasing 21 DVDs the membership is worth the money with a total spending of 104 dollars compared to 105 dollars without the membership.
Membership: -20, -24, -28, -32, -36, -40, -44, -48, -52, -56, -60, -64, -68, -72, -76, -80, -84, -88, -92, -96, -100, -104
No Membership: 0, -5, -10, -15, -20, -25, -30, -35, -40, -45, -50, -55, -60, -65, -70, -75, -80, -85, -90, -95, -100, -105
