another joint distribution question

P(X=x,Y=y)=1/8 for x =3,5 and y=1,2,4,7

P(X=x,Y=y)=0 otherwise

a) What is Fxy(x,y) for all x,y in R

b) What is pxy(x,y) for all x,y in R

c) What is px(x) for all x in R

d) What is py(y) for all y in R

e) What is the the marginal cdf Fx(x) for all x in R

f) What is the the marginal cdf Fy(y) for all y in R

My attempt

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a)

Fxy(x,y) =

y<1 1<=y<2 2<=y<4 4<=y<7 y<=7

x<3 0 0 0 0 0

3<=x<5 0 1/8 2/8 4/8 6/8

x<=5 0 2/8 4/8 6/8 8/8

1 if otherwise

b)

Pxy(X=x,Y=y)= 1/8 if x is 3,5 and y is 1,2,4,7

0 otherwise

c)