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Agent-Bond
Pe: 2009-11-05T19:58:05+02:00 In: In:

Exercitiu

Sa se rezolve :
√x-7 – 3√9-x = -2

Similare

5 raspunsuri

  1. ali
    maestru (V)

    Solutie: x=8
    Indicatie: ridici la patrat.

  2. Agent-Bond

        \[\begin{array}{l} \sqrt {x - 7} - 3\sqrt {9 - x} = - 2 \\ x - 7 - 6\sqrt {(x - 7)(9 - x)} + 9(9 - x) = 4 \\ x - 7 + 81 - 9x - 6\sqrt {(x - 7)(9 - x)} = 4 \\ - 8x + 74 - 6\sqrt {(x - 7)(9 - x)} = 4 \\ - 8x - 6\sqrt {(x - 7)(9 - x)} = - 70 \\ 8x + 6\sqrt {(x - 7)(9 - x)} = 70 \\ \end{array}\]

  4. Agent-Bond

    Si de aici nu ii dau de cap?!?!?!

  5. ali
    maestru (V) 
    *** QuickLaTeX cannot compile formula:

	\[
	\begin{array}{l}
	 6\sqrt {\left( {x - 7} \right)\left( {9 - x} \right)}  = 70 - 8x\left| {]
	
	
	

*** Error message:
\begin{array} on input line 10 ended by \end{document}.
leading text: \end{document}
Improper \prevdepth.
leading text: \end{document}
Missing $ inserted.
leading text: \end{document}
Missing } inserted.
leading text: \end{document}
Missing \right. inserted.
leading text: \end{document}
Missing } inserted.
leading text: \end{document}
Missing \cr inserted.
leading text: \end{document}
Missing $ inserted.
leading text: \end{document}
You can't use `\end' in internal vertical mode.
leading text: \end{document}
\begin{array} on input line 10 ended by \end{document}.
leading text: \end{document}
Missing } inserted.
leading text: \end{document}
Emergency stop.

    Ridici iarasi la a 2 si => ecuatie de grad 2 cu solutii x1 x2 care trebuie verficate(conform condiitilor de existenta a radicalului).

  6. Sigma2
    maestru (V)

    Ce parere aveti de urmatoarea varianta
    Se pun conditiile de existenta a radicalilor
    9-x>=0 =>X<9
    x-7>,=0 =>x>7
    xe [7,9] de aici se observa f usor ca x=8 solutie deja mentionata anterior
    unicitatea solutiei xe[7,8)

    0 =<radical(x-7)<1 rel1
    1< radical(9-x)=,<radical2 inmltim aceasta rel cu -3 si obtinem
    -3.>-3*radical(9-x)>=-3rad2 rel se mai poate scrie
    -3rad,2=<-3*rad(9-x)<-3 rel 2adunam rel1 si rel2 si obtinem
    rad(x-7)-3rad(9-x)<-2
    Analog demomstram pt xe(8,9]
    in final rezulta x=8 solutie unica

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