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ngoc tranbao
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Akai Haruma
3 tháng 8 2021 lúc 16:38

a. ĐKXĐ: $x\geq 1$

PT $\Leftrightarrow \frac{1}{2}\sqrt{x-1}-\frac{3}{2}.\sqrt{9}.\sqrt{x-1}+24.\sqrt{\frac{1}{64}}.\sqrt{x-1}=-17$

$\Leftrightarrow \frac{1}{2}\sqrt{x-1}-\frac{9}{2}\sqrt{x-1}+3\sqrt{x-1}=-17$

$\Leftrightarrow -\sqrt{x-1}=-17$

$\Leftrightarrow \sqrt{x-1}=17$

$\Leftrightarrow x-1=289$

$\Leftrightarrow x=290$

b. ĐKXĐ: $x\geq \frac{1}{2}$

PT $\Leftrightarrow \sqrt{9}.\sqrt{2x-1}-0,5\sqrt{2x-1}+\frac{1}{2}.\sqrt{25}.\sqrt{2x-1}+\sqrt{49}.\sqrt{2x-1}=24$

$\Leftrightarrow 3\sqrt{2x-1}-0,5\sqrt{2x-1}+2,5\sqrt{2x-1}+7\sqrt{2x-1}=24$
$\Leftrightarrow 12\sqrt{2x-1}=24$

$\Leftrihgtarrow \sqrt{2x-1}=2$

$\Leftrightarrow x=2,5$ (tm)

 

Akai Haruma
3 tháng 8 2021 lúc 16:42

c. ĐKXĐ: $x\geq 2$

PT $\Leftrightarrow \sqrt{36}.\sqrt{x-2}-15\sqrt{\frac{1}{25}}\sqrt{x-2}=4(5+\sqrt{x-2})$

$\Leftrightarrow 6\sqrt{x-2}-3\sqrt{x-2}=20+4\sqrt{x-2}$

$\Leftrightarrow \sqrt{x-2}=-20< 0$ (vô lý)

Vậy pt vô nghiệm

Akai Haruma
3 tháng 8 2021 lúc 16:44

d. ĐKXĐ: $x>\frac{-2}{3}$

PT $\Leftrightarrow \sqrt{\frac{1}{3x+2}}-\frac{1}{2}\sqrt{9}.\sqrt{\frac{1}{3x+2}}+\sqrt{16}.\sqrt{\frac{1}{3x+2}}-5\sqrt{\frac{1}{4}}\sqrt{\frac{1}{3x+2}}=1$

$\Leftrightarrow \sqrt{\frac{1}{3x+2}}-\frac{3}{2}\sqrt{\frac{1}{3x+2}}+4\sqrt{\frac{1}{3x+2}}-\frac{5}{2}\sqrt{\frac{1}{3x+2}}=1$

$\Leftrightarrow \sqrt{\frac{1}{3x+2}}=1$

$\Leftrightarrow \frac{1}{3x+2}=1$

$\Leftrightarrow 3x+2=1$

$\Leftrightarrow x=-\frac{1}{3}$

vũ linh
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Nguyễn Ngọc Lộc
1 tháng 7 2021 lúc 10:26

a, ĐKXĐ : \(x\ge1\)

Ta có ; \(PT\Leftrightarrow\dfrac{1}{2}\sqrt{x-1}-\dfrac{3}{2}.\sqrt{9}\sqrt{x-1}+24.\sqrt{\dfrac{1}{64}}\sqrt{x-1}=-17\)

\(\Leftrightarrow\sqrt{x-1}\left(\dfrac{1}{2}-\dfrac{3}{2}\sqrt{9}+24\sqrt{\dfrac{1}{64}}\right)=-17\)

\(\Leftrightarrow-\sqrt{x-1}=-17\)

\(\Leftrightarrow\sqrt{x-1}=17\)

\(\Leftrightarrow x=290\left(TM\right)\)

Vậy ....

b, ĐKXĐ : \(x\ge3\)

Ta có : \(PT\Leftrightarrow x-3-7\sqrt{x-3}+12=0\)

\(\Leftrightarrow\left[{}\begin{matrix}\sqrt{x-3}=4\\\sqrt{x-3}=3\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x-3=16\\x-3=9\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=19\\x=12\end{matrix}\right.\) ( TM )

Vậy ..

Nguyễn Lê Phước Thịnh
1 tháng 7 2021 lúc 10:29

a) Ta có: \(\dfrac{1}{2}\sqrt{x-1}-\dfrac{3}{2}\sqrt{9x-9}+24\sqrt{\dfrac{x-1}{64}}=-17\)

\(\Leftrightarrow\dfrac{1}{2}\sqrt{x-1}-\dfrac{9}{2}\sqrt{x-1}+3\sqrt{x-1}=-17\)

\(\Leftrightarrow-\sqrt{x-1}=-17\)

\(\Leftrightarrow x-1=17^2=289\)

hay x=290

Vậy: S={290}

b) Ta có: \(x-7\sqrt{x-3}+9=0\)

\(\Leftrightarrow x-7\sqrt{x-3}=-9\)

\(\Leftrightarrow x-3-2\cdot\sqrt{x-3}\cdot\dfrac{7}{2}+\dfrac{49}{4}=\dfrac{1}{4}\)

\(\Leftrightarrow\left(\sqrt{x-3}-\dfrac{7}{2}\right)^2=\dfrac{1}{4}\)

\(\Leftrightarrow\left[{}\begin{matrix}\sqrt{x-3}=4\\\sqrt{x-3}=3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x-3=16\\x-3=9\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=19\\x=12\end{matrix}\right.\)

Vậy: S={19;12}

hâyztohehe
1 tháng 7 2021 lúc 10:31

\(ĐKXĐ:x\ge1\) 

\(\Leftrightarrow\dfrac{1}{2}\sqrt{x-1}-\dfrac{3^2}{2}\sqrt{x-1}+\dfrac{24}{8}\sqrt{x-1}=-17\Leftrightarrow\dfrac{1}{2}-\dfrac{9}{2}\sqrt{x-1}+3\sqrt{x-1}=-17\) \(\Leftrightarrow-4\sqrt{x-1}+3\sqrt{x-1}=-17\Leftrightarrow-\sqrt{x-1}=-17\Leftrightarrow\sqrt{x-1}=17\Rightarrow x-1=289\Leftrightarrow x=290\left(TM\right)\) b \(ĐKXĐ:x\ge3\) 

\(\Leftrightarrow x-3-7\sqrt{x-3}+12=0\Leftrightarrow\left(\sqrt{x-3}-3\right)\left(\sqrt{x-3}-4\right)=0\Leftrightarrow\left[{}\begin{matrix}\sqrt{x-3}=3\\\sqrt{x-3}=4\end{matrix}\right.\)\(\Rightarrow\left[{}\begin{matrix}x-3=9\\x-3=16\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=12\left(TM\right)\\x=19\left(TM\right)\end{matrix}\right.\)

Lê Hương Giang
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Nguyễn Lê Phước Thịnh
30 tháng 8 2021 lúc 19:06

a: Ta có: \(\sqrt{4x+20}-3\sqrt{x+5}+\dfrac{4}{3}\sqrt{9x+45}=6\)

\(\Leftrightarrow2\sqrt{x+5}-3\sqrt{x+5}+4\sqrt{x+5}=6\)

\(\Leftrightarrow3\sqrt{x+5}=6\)

\(\Leftrightarrow x+5=4\)

hay x=-1

b: Ta có: \(\dfrac{1}{2}\sqrt{x-1}-\dfrac{3}{2}\sqrt{9x-9}+24\sqrt{\dfrac{x-1}{64}}=-17\)

\(\Leftrightarrow\dfrac{1}{2}\sqrt{x-1}-\dfrac{9}{2}\sqrt{x-1}+3\sqrt{x-1}=-17\)

\(\Leftrightarrow\sqrt{x-1}=17\)

\(\Leftrightarrow x-1=289\)

hay x=290

Nguyễn My
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Nguyễn Huy Tú
6 tháng 9 2017 lúc 21:09

2, \(\dfrac{1}{2}\sqrt{x+1}-\dfrac{3}{2}\sqrt{9x+9}+24\sqrt{\dfrac{x+1}{64}}=-17\)

\(\Leftrightarrow\dfrac{1}{2}\sqrt{x+1}-\dfrac{9}{2}\sqrt{x+1}+3\sqrt{x+1}=-17\)

\(\Leftrightarrow-\sqrt{x+1}=-17\)

\(\Leftrightarrow x+1=289\left(x>0\right)\)

\(\Leftrightarrow x=288\)

Vậy x = 288

3, \(-5x+7\sqrt{x}+12=0\)

\(\Leftrightarrow-5x+12\sqrt{x}-5\sqrt{x}+12=0\)

\(\Leftrightarrow\sqrt{x}\left(12-5\sqrt{x}\right)+\left(12-5\sqrt{x}\right)=0\)

\(\Leftrightarrow\left(\sqrt{x}+1\right)\left(12-5\sqrt{x}\right)=0\)

Do \(\sqrt{x}+1>0\)

\(\Rightarrow12-5\sqrt{x}=0\Leftrightarrow x=\dfrac{144}{25}\)

Vậy...

Trần Thiên Kim
6 tháng 9 2017 lúc 21:30

1. (Đề có chút sai sai nên mình sửa lại nhé) \(\sqrt{36x-36}-\sqrt{9x-9}-\sqrt{4x-4}=16-\sqrt{x-1}\)

(ĐK: \(x\ge1\))

\(\Leftrightarrow\sqrt{36\left(x-1\right)}-\sqrt{9\left(x-1\right)}-\sqrt{4\left(x-1\right)}=16-\sqrt{x-1}\)

\(\Leftrightarrow6\sqrt{x-1}-3\sqrt{x-1}-2\sqrt{x-1}+\sqrt{x-1}=16\)

\(\Leftrightarrow2\sqrt{x-1}=16\)

\(\Leftrightarrow\sqrt{x-1}=8\)

\(\Leftrightarrow x-1=64\)

\(\Leftrightarrow x=65\left(tm\right)\)

Vậy pt đã cho có nghiệm x=65.

2. \(\dfrac{1}{2}\sqrt{x+1}-\dfrac{3}{2}\sqrt{9x+9}+24\sqrt{\dfrac{x+1}{64}}=-17\)

(ĐK: \(x\ge-1\))

\(\Leftrightarrow\dfrac{1}{2}\sqrt{x+1}-\dfrac{3}{2}\sqrt{9\left(x+1\right)}+3\sqrt{x+1}=-17\)

\(\Leftrightarrow\dfrac{1}{2}\sqrt{x+1}-\dfrac{9}{2}\sqrt{x+1}+3\sqrt{x+1}=-17\)

\(\Leftrightarrow-\sqrt{x+1}=-17\)

\(\Leftrightarrow\sqrt{x+1}=17\)

\(\Leftrightarrow x+1=289\)

\(\Leftrightarrow x=288\left(tm\right)\)

Vậy \(S=\left\{288\right\}\)

3. \(-5x+7\sqrt{x}+12=0\) (ĐK: \(x\ge0\))

\(\Leftrightarrow5x-7\sqrt{x}-12=0\)

\(\Leftrightarrow5x+5\sqrt{x}-12\sqrt{x}-12=0\)

\(\Leftrightarrow5\sqrt{x}\left(\sqrt{x}+1\right)-12\left(\sqrt{x}+1\right)=0\)

\(\Leftrightarrow\left(\sqrt{x}+1\right)\left(5\sqrt{x}-12\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}\sqrt{x}+1=0\\5\sqrt{x}-12=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}\sqrt{x}=-1\left(vô.lý\right)\\5\sqrt{x}=12\end{matrix}\right.\Leftrightarrow\sqrt{x}=\dfrac{12}{5}\Leftrightarrow x=\dfrac{144}{25}\left(tm\right)\)

Vậy pt có nghiệm \(x=\dfrac{144}{25}\)

chang
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Tử Nguyệt Hàn
2 tháng 9 2021 lúc 9:33

\(a.\sqrt{x-1}+\sqrt{4x-4}-\sqrt{25x-25}+2=0\)( x lớn hơn hoặc =1)
\(\sqrt{x-1}+\sqrt{4\left(x-1\right)}-\sqrt{25\left(x-1\right)}\)+2=0
\(\sqrt{x-1}\left(1+\sqrt{4}-\sqrt{25}\right)=-2\)
\(\sqrt{x-1}\left(1+2-5\right)=-2\)
\(\sqrt{x-1}.\left(-2\right)=-2\)
\(\sqrt{x-1}=-2.2\)
\(\sqrt{x-1}-4\)(ko thỏa mãn)
b)
\(\dfrac{1}{2}\sqrt{x-1}-\dfrac{3}{2}\sqrt{9x-9}+24\sqrt{\dfrac{x-1}{64}}=-17\)
\(\dfrac{1}{2}\sqrt{x-1}-\dfrac{3}{2}\sqrt{9\left(x-1\right)}+24\dfrac{\sqrt{x-1}}{8}=-17\)
\(\dfrac{1}{2}\sqrt{x-1}-\dfrac{3}{2}.3\sqrt{x-1}+3\sqrt{x-1}=-17\)
\(\dfrac{1}{2}\sqrt{x-1}-\dfrac{9}{2}\sqrt{x-1}+3\sqrt{x-1}=-17\)
\(\left(\dfrac{1}{2}-\dfrac{9}{2}+3\right)\sqrt{x-1}=-17\)
\(7\sqrt{x-1}=-17\)
\(\sqrt{x-1}=-\dfrac{17}{7}\)(ko thỏa mãn căn bậc 2 ko có số âm)

Nguyễn Lê Phước Thịnh
2 tháng 9 2021 lúc 14:26

a: Ta có: \(\sqrt{x-1}+\sqrt{4x-4}-\sqrt{25x-25}+2=0\)

\(\Leftrightarrow\sqrt{x-1}+2\sqrt{x-1}-5\sqrt{x-1}=-2\)

\(\Leftrightarrow-2\sqrt{x-1}=-2\)

\(\Leftrightarrow x-1=1\)

hay x=2

Phương
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Anh Pha
20 tháng 10 2018 lúc 21:01

a,

\(\sqrt{1-4x+4x^2}=5\\ \sqrt{\left(2x-1\right)^2}=5\\ \left[{}\begin{matrix}2x-1=5\\2x-1=-5\end{matrix}\right.\\ \left[{}\begin{matrix}x=3\\x=-2\end{matrix}\right.\)

Anh Pha
20 tháng 10 2018 lúc 21:02

b,

\(\sqrt{4-5x}=12\\ 4-5x=144\\ x=-28\)

Anh Pha
20 tháng 10 2018 lúc 21:04

c,

\(\sqrt{x-1}+\sqrt{4\left(x-1\right)}-\sqrt{25\left(x-1\right)}+2=0\\ \sqrt{x-1}+2\sqrt{x-1}-5\sqrt{x-1}+2=0\\ 2\left(1-\sqrt{x-1}\right)=0\\ 1-\sqrt{x-1}=0\\ \sqrt{x-1}=1\\ x-1=1\\ x=2\)

Nga Phạm
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Akai Haruma
3 tháng 10 2018 lúc 22:37

Câu 1:

ĐK: \(x\geq \frac{-3}{2}\)

\(\sqrt{2x+3}=3-\sqrt{5}\)

\(\Rightarrow 2x+3=(3-\sqrt{5})^2=14-6\sqrt{5}\)

\(\Rightarrow x=\frac{11-6\sqrt{5}}{2}\)

Câu 2: ĐK: \(x\geq 0\)

\(\sqrt{5+\sqrt{7x}}=2+\sqrt{7}\)

\(\Rightarrow 5+\sqrt{7x}=(2+\sqrt{7})^2=11+4\sqrt{7}\)

\(\Rightarrow \sqrt{7x}=6+4\sqrt{7}\)

\(\Rightarrow 7x=(6+4\sqrt{7})^2\Rightarrow x=\frac{(6+4\sqrt{7})^2}{7}\)

Akai Haruma
3 tháng 10 2018 lúc 22:44

Câu 3: ĐK: \(x\geq 0\)

\((\sqrt{x}-2)(5-\sqrt{x})=4-x\)

\(\Leftrightarrow 5\sqrt{x}-x-10+2\sqrt{x}=4-x\)

\(\Leftrightarrow 7\sqrt{x}=14\Rightarrow \sqrt{x}=2\Rightarrow x=4\)

Câu 4: ĐK: \(x\ge 1\)

Sửa đề \(\frac{1}{2}\sqrt{x-1}-\frac{3}{2}\sqrt{9x-9}+24\sqrt{\frac{x-1}{64}}=-17\)

\(\Leftrightarrow \frac{\sqrt{x-1}}{2}-\frac{3}{2}\sqrt{9}.\sqrt{x-1}+24\sqrt{\frac{1}{64}}\sqrt{x-1}=-17\)

\(\Leftrightarrow \frac{\sqrt{x-1}}{2}-\frac{9\sqrt{x-1}}{2}+3\sqrt{x-1}=-17\)

\(\Leftrightarrow \sqrt{x-1}(\frac{1}{2}-\frac{9}{2}+3)=-17\)

\(\Leftrightarrow -\sqrt{x-1}=-17\Rightarrow \sqrt{x-1}=17\Rightarrow x=17^2+1=290\)

Trần Thu Trang
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Đặng Anh Thư
29 tháng 9 2017 lúc 5:06

a/ \(\dfrac{1}{2}.\sqrt{x-1}-\dfrac{3}{2}.\sqrt{9x-9}+24.\sqrt{\dfrac{x-1}{64}}=-17\) ( đkxđ : \(x\ge1\) )

\(\Leftrightarrow\dfrac{1}{2}.\sqrt{x-1}-\dfrac{3}{2}.\sqrt{3^2\left(x-1\right)}+24.\sqrt{\dfrac{x-1}{8^2}}=-17\)

\(\Leftrightarrow\dfrac{1}{2}.\sqrt{x-1}-\dfrac{3.3}{2}.\sqrt{x-1}+\dfrac{24}{8}\sqrt{x-1}=-17\)

\(\Leftrightarrow\) \(\dfrac{1}{2}\sqrt{x-1}-\dfrac{9}{2}\sqrt{x-1}+3\sqrt{x-1}=-17\)

\(\Leftrightarrow\left(\sqrt{x-1}\right)\left(\dfrac{1}{2}-\dfrac{9}{2}+3\right)=-17\)

\(\Leftrightarrow\sqrt{\left(x-1\right)}.\left(-1\right)=-17\)

\(\Leftrightarrow\sqrt{x-1}=\dfrac{-17}{-1}=17\)

\(\Leftrightarrow\left(\sqrt{x-1}\right)^2=17^2\)

\(\Leftrightarrow x-1=289\)

\(\Leftrightarrow x=289+1=290\)

vậy x= 290 là nghiệm của phương trình a

b/ \(3x-7\sqrt{x}+4=0\) ( đkxđ : \(x\ge0\) )

\(\Leftrightarrow3x-3\sqrt{x}-4\sqrt{x}+4=0\)

\(\Leftrightarrow3\sqrt{x}\left(\sqrt{x}-1\right)-4\left(\sqrt{x}-1\right)=0\)

\(\Leftrightarrow\left(3\sqrt{x}-4\right)\left(\sqrt{x}-1\right)=0\) \(\Leftrightarrow\left[{}\begin{matrix}3\sqrt{x}-4=0\\\sqrt{x}-1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}\sqrt{x}=\dfrac{4}{3}\\\sqrt{x}=1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{16}{9}\\x=1\end{matrix}\right.\)

vậy phương trình có tập nghiệm S=\(\left\{1;\dfrac{16}{9}\right\}\)

c/ \(-5x+7\sqrt{x}+12=0\) ( đkxđ: \(x\ge0\) )

\(\Leftrightarrow-\left(5x+5\sqrt{x}-12\sqrt{x}-12\right)=0\)

\(\Leftrightarrow-\left[5\sqrt{x}\left(\sqrt{x}+1\right)-12\left(\sqrt{x}+1\right)\right]\)= 0

\(\Leftrightarrow-\left(5\sqrt{x}-12\right)\left(\sqrt{x}+1\right)=0\)

\(x\ge0\Rightarrow\sqrt{x}\ge0\Leftrightarrow\sqrt{x}+1>0\)
\(\Rightarrow5\sqrt{x}-12=0\)

\(\Leftrightarrow\sqrt{x}=\dfrac{12}{5}\Rightarrow x=\dfrac{144}{25}\)

vậy \(x=\dfrac{144}{25}\) là nghiệm của phương trình c

Nguyễn Viết Duy
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Nguyễn Lê Phước Thịnh
4 tháng 8 2022 lúc 21:15

a: \(\Leftrightarrow\dfrac{2x-3}{x-1}=4\)

=>4x-4=2x-3

=>2x=1

hay x=1/2

b: \(\Leftrightarrow\sqrt{\dfrac{2x-3}{x-1}}=2\)

=>(2x-3)=4x-4

=>4x-4=2x-3

=>2x=1

hay x=1/2(nhận)

c: \(\Leftrightarrow\sqrt{2x+3}\left(\sqrt{2x-3}-2\right)=0\)

=>2x+3=0 hoặc 2x-3=4

=>x=-3/2 hoặc x=7/2

e: \(\Leftrightarrow2\sqrt{x-5}+\sqrt{x-5}-\sqrt{x-5}=4\)

=>căn (x-5)=2

=>x-5=4

hay x=9