See to answer this one you need to consider $(p,q)$ and $(q,p)$ as different results but (p,p) are considered as same results
Then we need to think how many possibilities are there if we throw red and green die simultaneously.There are 36 possibilities as follows:
$(1,1),(1,2),(1,3)....(1,6) $
$(2,1)....(2,6)$
...
$(6,1)....(6,6)$
then for getting $p[X=0]$ we have (1,1),(2,2)...(6,6) ,so there are 6 possibilites so $P[X=0]=\frac{6}{36}$ now doing similarly for $P[x=1]$ we have $(1,2),(2,1),(2,3),(3,2)....(5,6),(6,5)$ so we have 10 such possibilites. so $p[X=1]=\frac{10}{36}$
Now doing similarly for X=2,3,4,5,6 we get
$P[X=2]=\frac{8}{36}$, $P[X=3]=\frac{6}{36}$, $P[X=4]=\frac{4}{36}$, $P[X=5]=\frac{2}{36}$, $P[X=6]=\frac{0}{36}$