I already tried that.x can be 2^0,2^1,2^2or2^3 that is 4 ways ,2ways for 3and 4ways for 5.But what about y?
I thought of another method ,
using AM>GM,
x+y+z>=43 and max can be 3002 (when one of them is 3000 nd the other two 1 each.)
Then use multinomial theorem.Can this be done?