A shoe store developed the following estimated regression equation relating sales to inventory investment and advertising expenditures where y = 25 + 10x₁ + 8x₂ x₁= inventory investment ($1000s) x₂= advertising expenditures ($1000s) y = sales ($1000s) a. Predict the sales resulting from a $15,000 investment in inventory and an advertising budget of $10,000. b. Interpret b₁ and b₂ in this estimated regression equation.