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cum rezolv? x-3/x+1 >sau= 2x-5/x+2

Răspuns :

x-3/x+1=x-3=x+1⇒x-x=3+1⇒4
2x-5/x+2=2x-5=x+2⇒2x-x=5+2⇒x=7
sucees
[tex]\dfrac{x-3}{x+1}\ \geq\ \dfrac{2x-5}{x+2}\Leftrightarrow \dfrac{x-3}{x+1}\ -\ \dfrac{2x-5}{x+2}\ \geq\ 0\Leftrightarrow \\\;\\ \Leftrightarrow \dfrac{(x-3)(x+2) - (x+1)(2x-5)}{(x+1)(x+2)} \geq 0[/tex]

Dupa efectuarea calculelor de la numarator, obtinem:

[tex]\dfrac{-(x-1)^2}{(x+1)(x+2)}\geq0|_{\cdot\ (-1)} \Leftrightarrow \dfrac{(x-1)^2}{(x+1)(x+2)}\leq 0\Leftrightarrow \begin{cases} (x+1)(x+2)\ \ \textless \ 0\\\;\\ x-1 = 0 \end{cases} \\\;\\ S\ =\ (-1,\ -2) \cup\ \{1\}[/tex]