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Aduceti la forma cea mai simpla:
[tex]a) \frac{x-1}{ x^{2}-x+1 }- \frac{2x-2}{ x^{3}+1 }; [/tex]
[tex]b) \frac{2x-1}{ x^{3}-1 }- \frac{x}{x-1}+1.[/tex]


Răspuns :

a) numitorul comun x³+1=(x+1)(x²-x+1)
[(x-1)(x+1)-2x+2]/(x³+1)=(x²-1-2x+2)/(x³+1)=(x²-2x+1)/(x³+1)=(x-1)²/(x³+1)
b) x³-1=(x-1)(x²+x+1)
[2x-1-x(x²+x+1)+x³-1]/(x³-1)=(2x-1-x³-x²-x+x³-1)/(x³-1)=(-x²+x-2)/(x³-1)=(x²-x+2)/(1-x³)