The demand function for Widgets is given by QD = 6880 - 22y - 18p - 7pG, where QD is the quantity of widgets demanded, y is the per capita income, and pG is the price of Gizmos. What is the slope of the demand curve for Widgets?
QD = -22
QD = 18
QD = -7
QD = -6880
None of the Above