\(\sqrt{x^2+48}=4x-3+\sqrt{x^2+35}\)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(pt\Leftrightarrow\sqrt{x^2+48}-7=4x-4+\sqrt{x^2+35}-6\)
\(\Leftrightarrow\dfrac{\left(\sqrt{x^2+48}-7\right)\left(\sqrt{x^2+48}+7\right)}{\sqrt{x^2+48}+7}=4\left(x-1\right)+\dfrac{\left(\sqrt{x^2+35}-6\right)\left(\sqrt{x^2+35}+6\right)}{\sqrt{x^2+35}+6}\)
\(\Leftrightarrow\dfrac{\left(x-1\right)\left(x+1\right)}{\sqrt{x^2+48}+7}-4\left(x-1\right)-\dfrac{\left(x+1\right)\left(x-1\right)}{\sqrt{x^2+35}+6}=0\)
\(\Leftrightarrow\left(x-1\right)\left(\dfrac{x+1}{\sqrt{x^2+48}+7}-4-\dfrac{x+1}{\sqrt{x^2+35}+6}\right)=0\)
Do : \(\dfrac{x+1}{\sqrt{x^2+48}+7}-4-\dfrac{x+1}{\sqrt{x^2+35}+6}\ne0\)
\(\Rightarrow x=1\)
\(\sqrt{x^2+48}=4x-3+\sqrt{x^2+35}\Leftrightarrow\sqrt{x^2+48}-7=4x-4+\sqrt{x^2+35}-6\)
\(\Leftrightarrow\frac{x^2+48-49}{\sqrt{x^2+48}+7}=4x-4+\frac{x^2+35-36}{\sqrt{x^2+35}+6}\Leftrightarrow\frac{x^2-1}{\sqrt{x^2+48}+7}=4\left(x-1\right)+\frac{x^2-1}{\sqrt{x^2+35}+6}\)
\(\Leftrightarrow\left(x-1\right)\left(\frac{x+1}{\sqrt{x^2+48}+7}-4-\frac{x+1}{\sqrt{x^2+35}+6}\right)=0\)\(\Leftrightarrow x-1=0\Leftrightarrow x=1\).
VÌ \(\sqrt{x^2+48}-\sqrt{x^2+35}>0\)
=> \(x>\frac{3}{4}\)
Phương trình tương đương
\((x+6-\sqrt{x^2+48})+3\left(x-1\right)+\left(\sqrt{x^2+35}-6\right)=0\)
=> \(\frac{12\left(x-1\right)}{x+6+\sqrt{x^2+48}}+3\left(x-1\right)+\frac{x^2-1}{\sqrt{x^2+35}+6}=0\)
\(\hept{\begin{cases}x=1\\\frac{12}{x+6+\sqrt{x^2+48}}+3+\frac{x+1}{\sqrt{x^2+35}+6}=0\left(2\right)\end{cases}}\)
Phương trình (2) vô nghiệm do x>3/4=> VT>0
\(\sqrt{x^2+48}=4x-3+\sqrt{x^2+35}\)
\(\Leftrightarrow\sqrt{x^2+48}-7=4x-4+\sqrt{x^2+35}-6\)
\(\Leftrightarrow\frac{x^2+48-49}{\sqrt{x^2+48}+7}=4\left(x-1\right)+\frac{x^2+35-36}{\sqrt{x^2+35}+6}\)
\(\Leftrightarrow\frac{x^2-1}{\sqrt{x^2+48}+7}-4\left(x-1\right)-\frac{x^2-1}{\sqrt{x^2+35}+6}=0\)
\(\Leftrightarrow\left(x-1\right)\left(\frac{x+1}{\sqrt{x^2+48}+7}-4-\frac{x+1}{\sqrt{x^2+35}+6}\right)=0\)
\(\Rightarrow x-1=0\Rightarrow x=1\)
a)\(\sqrt{x^2+48}=4x-3+\sqrt{x^2+35}\)
\(\Leftrightarrow\sqrt{x^2+48}-7=4x-4+\sqrt{x^2+35}-6\)
\(\Leftrightarrow\dfrac{x^2+48-49}{\sqrt{x^2+48}+7}=4\left(x-1\right)+\dfrac{x^2+35-36}{\sqrt{x^2+35}+6}\)
\(\Leftrightarrow\dfrac{x^2-1}{\sqrt{x^2+48}+7}-4\left(x-1\right)-\dfrac{x^2-1}{\sqrt{x^2+35}+6}=0\)
\(\Leftrightarrow\left(x-1\right)\left(\dfrac{x+1}{\sqrt{x^2+48}+7}-4-\dfrac{x+1}{\sqrt{x^2+35}+6}\right)=0\)
\(\Rightarrow x-1=0\Rightarrow x=1\)
b)\(\left(\sqrt{x-1}+1\right)^3+2\sqrt{x-1}=2-x\)
\(pt\Leftrightarrow\left(\sqrt{x-1}+1\right)^3-1+2\sqrt{x-1}=1-x\)
\(\Leftrightarrow\left(\sqrt{x-1}+1-1\right)\left(\left(\sqrt{x-1}+1\right)^6+\left(\sqrt{x-1}+1\right)^3+1\right)+2\sqrt{x-1}-\left(1-x\right)=0\)
\(\Leftrightarrow\sqrt{x-1}\left(\left(\sqrt{x-1}+1\right)^6+\left(\sqrt{x-1}+1\right)^3+1\right)+2\sqrt{x-1}+x-1=0\)
\(\Leftrightarrow\sqrt{x-1}\left(\left(\sqrt{x-1}+1\right)^6+\left(\sqrt{x-1}+1\right)^3+3+\sqrt{x-1}\right)=0\)
Dễ thấy: \(\left(\sqrt{x-1}+1\right)^6+\left(\sqrt{x-1}+1\right)^3+3+\sqrt{x-1}>0\)
\(\Rightarrow\sqrt{x-1}=0\Rightarrow x-1=0\Rightarrow x=1\)
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: ĐKXĐ: x-5>=0
=>x>=5
\(\sqrt{4x-20}+\sqrt{x-5}-\dfrac{1}{3}\cdot\sqrt{9x-45}=4\)
=>\(2\sqrt{x-5}+\sqrt{x-5}-\dfrac{1}{3}\cdot3\sqrt{x-5}=4\)
=>\(2\sqrt{x-5}=4\)
=>x-5=4
=>x=9(nhận)
b: ĐKXĐ: x-1>=0
=>x>=1
\(\sqrt{x-1}+\sqrt{4x-4}-\sqrt{25x-25}=4\)
=>\(\sqrt{x-1}+2\sqrt{x-1}-5\sqrt{x-1}=4\)
=>\(-2\sqrt{x-1}=4\)
=>\(\sqrt{x-1}=-2\)(vô lý)
Vậy: Phương trình vô nghiệm
c: ĐKXĐ: x-2>=0
=>x>=2
\(\dfrac{1}{3}\sqrt{x-2}-\dfrac{2}{3}\cdot\sqrt{9x-18}+6\cdot\sqrt{\dfrac{x-2}{81}}=-4\)
=>\(\dfrac{1}{3}\sqrt{x-2}-\dfrac{2}{3}\cdot3\sqrt{x-2}+6\cdot\dfrac{\sqrt{x-2}}{9}=-4\)
=>\(\sqrt{x-2}\left(\dfrac{1}{3}-2+\dfrac{2}{3}\right)=-4\)
=>\(-\sqrt{x-2}=-4\)
=>x-2=16
=>x=18(nhận)
d: ĐKXĐ: x+3>=0
=>x>=-3
\(\sqrt{9x+27}+4\sqrt{x+3}-\dfrac{3}{4}\cdot\sqrt{16x+48}=0\)
=>\(3\sqrt{x+3}+4\sqrt{x+3}-\dfrac{3}{4}\cdot4\sqrt{x+3}=0\)
=>\(4\sqrt{x+3}=0\)
=>x+3=0
=>x=-3(nhận)
a) \(\sqrt{4x-20}+\sqrt{x-5}-\dfrac{1}{3}\sqrt{9x-45}=4\)
= \(2\sqrt{x-5}+\sqrt{x-5}-\dfrac{1}{3}\sqrt{9\left(x-5\right)}=4\)
= \(2\sqrt{x-5}+\sqrt{x-5}-\sqrt{x-5}=4\)
= \(2\sqrt{x-5}=4\)
= \(\sqrt{x-5}=2\)
= \(\left|x-5\right|=4\)
=> \(x-5=\pm4\)
\(x=\pm4+5\)
\(x=9;x=1\)
Vậy x=9; x=1