When the price of salad was $5, a cafeteria sold 50 packets of salad dressing a day at $0.50 per packet. When they raised the price of salad to $7 but kept the dressing at the same price, they sold only 25 packets of dressing per day. This graph shows the elasticity of demand for salad and dressing.

Using the mid-point formula, the cross-price elasticity is __________ and the goods are __________.

0.5, substitutes

-0.5, complements

2, substitutes

-2, complements