How do I solve and graph questions a through g? Please help!

The demand curve is given by

QD= 500-5Px+0.5I + 10PY- 2Pz where

QD= quantity demanded of good X

PX=price of good X

I=consumer income, in thousands

PY=price of good Y

PZ=price of good Z

a.Based on the demand curve above, is X a normal or an inferior good and why?

b. Based on the demand curve above, what is the relationship between good X and good Y? Why?

c. Based on the demand curve above, what is the relationship between good X and good Z?

d. what is the equation of the demand curve if consumer incomes are $30,000, the price of good Y is $10 and the price of good Z is $20?

e. Graph the demand curve that you found in (d), showing intercepts and slopes

f. If the pirce of good X is $15. what is the quantity demanded? Show this point on your demand curve.

g. Now suppose the price of good Y rises to $15. Graph the new demand curve, label and show your work.