7. In the accompanying graph, is the slope of curve AA’ positive or negative? Does the slope increase or decrease as we move along the curve from A to A’? Answer the same two questions for curve BB’.

50 40 30 20 10 0 2

(2, 10)

(26, 10)

(12, 50) (16, 50)

4 6 a c X X

A C b b

a c

B