Suppose the own price elasticity of demand for goodXis -3, its income elasticity is -3, its advertising elasticity is 4, and the cross-price elasticity of demand between it and goodYis 2.

Determine how much the consumption of this good will change if:

a. The price of goodXdecreases by 7 percent.

b. The price of goodYincreases by 9 percent.

c. Advertising decreases by 2 percent.

d. Income increases by 5 percent.