obadismal obadismal
  • 15-03-2018
  • Mathematics
contestada

solving radical equations
check for extraneous solutions
[tex] \sqrt{2x + 30} = x + 3[/tex]

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lenlee lenlee
  • 15-03-2018
I don’t know this question
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jdoe0001 jdoe0001
  • 15-03-2018
[tex]\bf \sqrt{2x+30}=x+3\impliedby \textit{we'll squares both sides} \\\\\\ (\sqrt{2x+30})^2=(x+3)^2\implies 2x+30=x^2+6x+9 \\\\\\ 0=x^2+4x-21\implies 0=(x+7)(x-3)\implies x= \begin{cases} -7\\ 3 \end{cases}[/tex]

I don't see  an extraneous value there, -7 checks out well if you plug it in the original equation, and so does 3.
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