Ex 5 va rog frumos. Dau coronita

Răspuns:
Explicație pas cu pas:
[tex]E(x)=[1-2\frac{x-1}{x+1 } +(\frac{x-1}{x+1} )^{2}]\frac{(x-1)(x+1)}{4} =(\frac{x-1}{x+1}-1 ) ^{2} \frac{(x-1)(x+1)}{4}=(\frac{-2}{x+1} )^{2} \frac{(x-1)(x+1)}{4}=\\ = \frac{x-1}{x+1}[/tex]