Triangle wavefunction - position uncertainty and probability amplitude

1. The problem statement, all variables and given/known data

Hey guys. Basically I have a wavefunction that looks like this





I have to find:

(a) The normalization constant N, of course by normalizing it

(b) Find <x> and <x^2> and use this to find Δx.



2. Relevant equations

I'm just gona insert images, as i'm writing it all with my tablet:







3. The attempt at a solution

Okay, so I've found the normalization constant, N, but I've got 2 different answers depending on the way in which I solve the problem, and I want to know which is correct (and why, if possible). Please view the image below:





So...which is correct? :S



I need to know the explicit expression for the probability density to proceed further.



Thanks a lot guys!

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