Y~N(0， 1)

X standard words need to be put here first.

Let U=(X- 1)/ "radical number 2", and the distribution of U~N(0, 1) is the same as y,

Then X=U times "root number 2"+1.

Because Z=2X-Y+3, X and Y are independent.

replace

Get Z= twice the "root number 2" multiplied by Y+Y+5.

It is concluded that the distribution of z is n (5 5,4 times the root number 2).