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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 9: a)Căn 1-3x =4 b)Căn x^2 + 4x + 4 = 2

Toán Lớp 9: a)Căn 1-3x =4
b)Căn x^2 + 4x + 4 = 2

Comments ( 2 )

  1. a)$\sqrt{1-3x}$ $=$ $4$
    $1-3x$ = $16$
    $3x$ = $-15$
    $x$ $=$ $-5$
    b)$\sqrt{x^{2}+4x+4}$ $=$ $2$
    $\sqrt{(x+2)^{2}}$ $=$ $2$
    $|x+2|$ $=$ $2$
    \(\left[ \begin{array}{l}x+2=2\\x+2=-2\end{array} \right.\)
    \(\left[ \begin{array}{l}x=0\\x=-4\end{array} \right.\)

  2. Giải đáp:
    a. sqrt{1-3x}=4
    <=> 1-3x=16
    <=> -3x=15
    <=> x=-5
    Vậy S={-5}
    b. sqrt{x^2+4x+4}=2
    <=> sqrt{(x+2)^2}=2
    <=> |x+2|=2
    <=>\(\left[ \begin{array}{l}x+2=2\\x+2=-2\end{array} \right.\) 
    <=>\(\left[ \begin{array}{l}x=0\\x=-4\end{array} \right.\) 
    Vậy S={-4;0}

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222-9+11+12:2*14+14 = ? ( )