Question

is x+2y+3z is equivalent to z+y+z+x+y+z

Answer 1

Yes because U can only add like valuables

Answer 2

I believe it is equivalent.

There is 1  "x"  in x+2y+3z and in  z+y+z+x+y+z

There are 2  "y's" in  z+y+z+x+y+z and in x+2y+3z

There are 3  "z's"  in x+2y+3z and in z+y+z+x+y+z

So, yes they should be equal