Sarah's preferences are represented by U(x;y)= x^2y^3. Her income is $1,000, the price ofxis $5, and the price ofyis $20. If

the price ofxfalls to $4, calculate the (a) slutsky substitution (b) Income and (c) total effect of the price decrease on the

demand of x. Set up the Lagrange to find all the demands.