Your answer would be
Y=3
X=2.5
Take 2y+3x=9
either the Y or the X (which ever you are trying to find) Then divide by the number on the opposite side (which in this case would be nine)
So, 9/2=2.5 then your left with y, so y=2.5
Then for X, 9/3=3, then your left with X, so x=3
Hope this helps :]