Suppose the own price elasticity of demand for goodXis -3, its income elasticity is 1, its advertising elasticity is 2, and the cross-price elasticity of demand between it and goodYis -4. Determine how much the consumption of this good will change if:

a. The price of goodXdecreases by 5 percent.

b. The price of goodYincreases by 8 percent.

c. Advertising decreases by 4 percent.

d. Income increases by 4 percent.