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\(\Leftrightarrow\left|2x+1\right|=\left|x+6\right|\)
\(\Leftrightarrow\left[{}\begin{matrix}2x+1=x+6\\2x+1=-x-6\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=-\dfrac{7}{3}\end{matrix}\right.\)
d. \(\sqrt{9x^2+12x+4}=4\)
<=> \(\sqrt{\left(3x+2\right)^2}=4\)
<=> \(|3x+2|=4\)
<=> \(\left[{}\begin{matrix}3x+2=4\\3x+2=-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}3x=2\\3x=-6\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{3}\\x=-2\end{matrix}\right.\)
c: Ta có: \(\dfrac{5\sqrt{x}-2}{8\sqrt{x}+2.5}=\dfrac{2}{7}\)
\(\Leftrightarrow35\sqrt{x}-14=16\sqrt{x}+5\)
\(\Leftrightarrow x=1\)
`a, <=> 5/3 . 3sqrt(x^2+2) + 3/2.2sqrt(x^2+2)-7sqrt6=sqrt(x^2+2)`
`= (5+3-1)sqrt(x^2+2)=7sqrt6`
`<=> 7sqrt(x^2+2)=7sqrt6`.
`<=> x^2+2=36`.
`<=> x^2=34`.
`<=> x=+-sqrt(34)`.
Vậy...
`b, sqrt(4x^2-12x+9)-6=0`
`<=> |2x-3|=6`.
`@ x >=3/2 <=> 2x-3=6.`
`<=> x=9/2 (tm)`.
`@x <3/2 <=> 3-2x=6`
`<=> 2x=-3`
`<=> x=-3/2.`
Vậy...
a. ĐKXĐ: $x\geq 2$ hoặc $x=1$
PT $\Leftrightarrow \sqrt{(x-1)(x-2)}=\sqrt{x-1}$
$\Leftrightarrow \sqrt{x-1}(\sqrt{x-2}-1)=0$
\(\Leftrightarrow \left[\begin{matrix} \sqrt{x-1}=0\\ \sqrt{x-2}-1=0\end{matrix}\right.\Leftrightarrow \left[\begin{matrix} x=1\\ x=3\end{matrix}\right.\) (đều thỏa mãn)
b.
PT $\Leftrightarrow \sqrt{(x-2)^2}=\sqrt{(2x-3)^2}$
$\Leftrightarrow |x-2|=|2x-3|$
\(\Leftrightarrow \left[\begin{matrix} x-2=2x-3\\ x-2=3-2x\end{matrix}\right.\Leftrightarrow \left[\begin{matrix} x=1\\ x=\frac{5}{3}\end{matrix}\right.\)
c. ĐKXĐ: $x=2$ hoặc $x\geq 3$
PT $\Leftrightarrow \sqrt{(x-2)(x-3)}=\sqrt{x-2}$
$\Leftrightarrow \sqrt{x-2}(\sqrt{x-3}-1)=0$
\(\Leftrightarrow \left[\begin{matrix} \sqrt{x-2}=0\\ \sqrt{x-3}-1=0\end{matrix}\right.\Leftrightarrow \left[\begin{matrix} x=2\\ x=4\end{matrix}\right.\) (đều tm)
d.
PT $\Leftrightarrow \sqrt{(2x-1)^2}=\sqrt{(x-3)^2}$
$\Leftrightarrow |2x-1|=|x-3|$
\(\Leftrightarrow \left[\begin{matrix} 2x-1=x-3\\ 2x-1=3-x\end{matrix}\right.\Leftrightarrow \left[\begin{matrix} x=-2\\ x=\frac{4}{3}\end{matrix}\right.\)
`a)\sqrt{3x}-5\sqrt{12x}+7\sqrt{27x}=12` `ĐK: x >= 0`
`<=>\sqrt{3x}-10\sqrt{3x}+21\sqrt{3x}=12`
`<=>12\sqrt{3x}=12`
`<=>\sqrt{3x}=1`
`<=>3x=1<=>x=1/3` (t/m)
`b)5\sqrt{9x+9}-2\sqrt{4x+4}+\sqrt{x+1}=36` `ĐK: x >= -1`
`<=>15\sqrt{x+1}-4\sqrt{x+1}+\sqrt{x+1}=36`
`<=>12\sqrt{x+1}=36`
`<=>\sqrt{x+1}=3`
`<=>x+1=9`
`<=>x=8` (t/m)
a) \(x+\sqrt{4x^2-4x+1}=2\)
\(\Leftrightarrow x+\sqrt{\left(2x-1\right)^2}=2\)
\(\Leftrightarrow x+|2x-1|=2\)
\(TH1:x\ge0\)
\(\Leftrightarrow x+2x-1=2\)
\(\Leftrightarrow3x-1=2\)
\(\Leftrightarrow3x=3\)
\(\Leftrightarrow x=1\left(TM\right)\)
\(TH2:x< 0\)
\(\Leftrightarrow x-2x-1=2\)
\(\Leftrightarrow-x-1=2\)
\(\Leftrightarrow-x=3\)
\(\Leftrightarrow x=-3\left(TM\right)\)
Vậy:...
b) \(3x-1-\sqrt{4x^2-12x+9}=0\)
\(\Leftrightarrow3x-1-\sqrt{\left(2x-3\right)^2}=0\)
\(\Leftrightarrow3x-1-|2x-3|=0\)
\(TH1:x\ge0\)
\(\Leftrightarrow3x-1-2x+3=0\)
\(\Leftrightarrow x+2=0\Leftrightarrow x=-2\left(KTM\right)\)
\(TH2:x< 0\)
\(\Leftrightarrow3x-1+2x-3=0\)
\(\Leftrightarrow5x-4=0\Leftrightarrow x=\frac{4}{5}\left(KTM\right)\)
Vậy: pt vô nghiệm
Học Tốt!!!
\(\Leftrightarrow\sqrt{3\left(2x+1\right)^2+4}+\sqrt{\left(2x+1\right)^2}+\left(2x+1\right)^2=2\)
Do \(\left\{{}\begin{matrix}\sqrt{3\left(2x+1\right)^2+4}\ge2\\\sqrt{\left(2x+1\right)^2}\ge0\\\left(2x+1\right)^2\ge0\end{matrix}\right.\) \(\Rightarrow VT\ge2\)
Dấu "=" xảy ra khi và chỉ khi \(2x+1=0\Leftrightarrow x=-\frac{1}{2}\)
Pt có nghiệm duy nhất \(x=-\frac{1}{2}\)