Te extended demand function of good x is qdx1200 - 10px

Question

The extended demand function of good X is:

Qd^X=1200 - 10Px + 20Py + 0.2M

Where Qd^X = quantity demanded of good X

PX = Price of good X

M = Average consumer income

Py = Price of related good Y (related in consumption of good X)

a) If M = 20000, Py = 10, and Px = 400 then Qd^X =

If M = 20000, Py = 10, and Px = 420 then Qd^X =