# probability – Find \$ X \$ in \$ P (-x

I tried:

$$P (-x <10 – x 0) = 0.95$$

This makes no sense? Why?

$$mu = 10$$ and the standard deviation is $$2$$.

I found this: link

I can see that the OP basically did what I did, but did the standardization directly. Why does it work if it's done that way and it doesn't work like I did?

For comparison, here is a problem using a standard normal curve:

$$P (-z

Then I look it up in table Z etc. My question is, why does what I tried to do work here but not in the first problem?