Answer:

If A(a - 2 , -1), B(2a, 0), C(4,b) and D(1, 2) are the vertices of a parallelogram, then the values of a and b.

Step-by-step explanation:

I also think it is incorrect question

Answer:

Henry Baker – An elderly, poor man whose loss of a hat and a goose is what first pulls Holmes into the case of the Blue Carbuncle. James Ryder – Hotel employee and thief. Peterson the Commissionaire – Hotel employee and friend of Holmes's who brings him the hat and the goose that belong to Henry Baker.