A. The price of good x decreases by 6 percent?

Price elasticity of demand (PED) = percentage change in quantity / percentage change in price

But PED = -2

percentage change in price = -6%

hence

-2 = %change in quantity / -6%

%change in quantity = -2 * -6% = 12%

If price of good declines by 6%, Consumption will increase by 12%.

B. The price of good y increases by 8?

Cross Price Elasticity of Demand (XED) = %Change in Quantity Demanded of Good x / %Change in Price of Good y

But XED = -4

%Change in Price of Good Y = 8%

Hence,

-4 = %Change in Quantity Demanded of Good x / 8%

%Change in Quantity Demanded of Good = -4 * 8% = -32%

C. Advertising decreases b 4 percent?

Advertising elasticity of demand (AED) = the percentage change in the quantity demanded / the percentage change in advertising expenditures

But

AED = 2

The percentage change in advertising expenditures = - 4%

2 = the percentage change in advertising expenditures / -4%

the percentage change in advertising expenditures = 2 * -4% = -8%

D. Income increases by 5 percent?

Income elasticity of demand (YED) = %change in demand / %change in income

But

YED = 3

%change in income = 5%

3 = %change in demand / 5%

%change in demand = 3 * 5% = 15%