giải phương trình: \(\sqrt{5x-1}-\sqrt{3x-2}-\sqrt{x-1}=0\)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
ĐKXĐ:
\(\left(2x+2-2\sqrt{5x-1}\right)+\left(\sqrt{5x^2+x+3}-\left(2x+1\right)\right)+x^2-3x+2=0\)
\(\Leftrightarrow\dfrac{2\left(x^2-3x+2\right)}{x+1+\sqrt{5x-1}}+\dfrac{x^2-3x+2}{\sqrt{5x^2+x+3}+2x+1}+x^2-3x+2=0\)
\(\Leftrightarrow\left(x^2-3x+2\right)\left(\dfrac{2}{x+1+\sqrt{5x-1}}+\dfrac{1}{\sqrt{5x^2+x+3}+2x+1}+1\right)=0\)
\(\Leftrightarrow x^2-3x+2=0\)
5: ĐKXĐ: \(\frac{x+3}{x-7}>0\)
=>x>7 hoặc x<-3
Ta có: \(\left(x-7\right)\cdot\sqrt{\frac{x+3}{x-7}}=x+4\)
=>\(\sqrt{\left(x+3\right)\left(x-7\right)}=x+4\)
=>\(\begin{cases}x+4\ge0\\ \left(x+3\right)\left(x-7\right)=\left(x+4\right)^2\end{cases}\Rightarrow\begin{cases}x\ge-4\\ x^2-4x-21=x^2+8x+16\end{cases}\)
=>\(\begin{cases}x\ge-4\\ -12x=37\end{cases}\Rightarrow x=-\frac{37}{12}\) (nhận)
6: ĐKXĐ: x>=4
Ta có: \(2\sqrt{x-4}+\sqrt{x-1}=\sqrt{2x-3}+\sqrt{4x-16}\)
=>\(2\sqrt{x-4}+\sqrt{x-1}=\sqrt{2x-3}+2\sqrt{x-4}\)
=>\(\sqrt{2x-3}=\sqrt{x-1}\)
=>2x-3=x-1
=>2x-x=-1+3
=>x=2(loại)
7: ĐKXĐ: x>=1
Ta có: \(\sqrt{x+2\sqrt{x-1}}+\sqrt{x-2\sqrt{x-1}}=\frac{x+3}{2}\)
=>\(\sqrt{x-1+2\cdot\sqrt{x-1}+1}+\sqrt{x-1-2\cdot\sqrt{x-1}\cdot1+1}=\frac{x+3}{2}\)
=>\(\sqrt{\left(\sqrt{x-1}+1\right)^2}+\sqrt{\left(\sqrt{x-1}-1\right)^2}=\frac{x+3}{2}\)
=>\(\sqrt{x-1}+1+\left|\sqrt{x-1}-1\right|=\frac{x+3}{2}\) (1)
TH1: \(\sqrt{x-1}-1\ge0\)
=>\(\sqrt{x-1}\ge1\)
=>x-1>=1
=>x>=2
(1) sẽ trở thành: \(\sqrt{x-1}+1+\sqrt{x-1}-1=\frac{x+3}{2}\)
=>\(2\sqrt{x-1}=\frac{x+3}{2}\)
=>\(4\sqrt{x-1}=x+3\)
=>\(16\left(x-1\right)=\left(x+3\right)^2\)
=>\(x^2+6x+9=16x-16\)
=>\(x^2-10x+25=0\)
=>\(\left(x-5\right)^2=0\)
=>x-5=0
=>x=5(nhận)
TH2: \(\sqrt{x-1}-1<0\)
=>\(\sqrt{x-1}<1\)
=>0<=x-1<1
=>1<=x<2
(1) sẽ trở thành: \(\sqrt{x-1}+1+1-\sqrt{x-1}=\frac{x+3}{2}\)
=>\(\frac{x+3}{2}=2\)
=>x+3=4
=>x=1(nhận)
\(a,PT\Leftrightarrow\left|x+3\right|=3x-6\\ \Leftrightarrow\left[{}\begin{matrix}x+3=3x-6\left(x\ge-3\right)\\x+3=6-3x\left(x< -3\right)\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{9}{2}\left(tm\right)\\x=\dfrac{3}{4}\left(ktm\right)\end{matrix}\right.\\ \Leftrightarrow x=\dfrac{9}{2}\\ b,PT\Leftrightarrow\left|x-1\right|=\left|2x-1\right|\\ \Leftrightarrow\left[{}\begin{matrix}x-1=2x-1\\1-x=2x-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{2}{3}\end{matrix}\right.\)
\(c,ĐK:x\le\dfrac{2}{5}\\ PT\Leftrightarrow4-5x=25x^2-20x+4\\ \Leftrightarrow25x^2-15x=0\\ \Leftrightarrow5x\left(5x-3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\left(tm\right)\\x=\dfrac{3}{5}\left(ktm\right)\end{matrix}\right.\Leftrightarrow x=0\\ d,ĐK:x\le\dfrac{2}{5}\\ PT\Leftrightarrow4-5x=2-5x\\ \Leftrightarrow x\in\varnothing\)
1. 3x( x - 2 ) - ( x - 2 ) = 0
<=> ( x-2).(3x-1) = 0 => x = 2 hoặc x = \(\dfrac{1}{3}\)
2. x( x-1 ) ( x2 + x + 1 ) - 4( x - 1 )
<=> ( x - 1 ).( x (x^2 + x + 1 ) - 4 ) = 0
(phần này tui giải được x = 1 thôi còn bên kia giải ko ra nha )
3 \(\left\{{}\begin{matrix}\sqrt{5}x-2y=7\\\sqrt{5}x-5y=10\end{matrix}\right.\)<=> \(\left\{{}\begin{matrix}y=-1\\x=\sqrt{5}\end{matrix}\right.\)
\(1. 3x^2 - 7x +2=0\)
=>\(Δ=(-7)^2 - 4.3.2\)
\(= 49-24 = 25\)
Vì 25>0 suy ra phương trình có 2 nghiệm phân biệt:
\(x_1\)=\(\dfrac{-\left(-7\right)+\sqrt{25}}{2.3}=\dfrac{7+5}{6}=2\)
\(x_2\)=\(\dfrac{-\left(-7\right)-\sqrt{25}}{2.3}=\dfrac{7-5}{6}=\dfrac{1}{3}\)
\(\sqrt{3x+1}+2\sqrt{x+3}=3\sqrt{5x-1}\)
=>\(\sqrt{3x+1}-2+2\sqrt{x+3}-4=3\sqrt{5x-1}-6\)
=>\(\dfrac{3x+1-4}{\sqrt{3x+1}+2}+2\left(\sqrt{x+3}-2\right)-3\left(\sqrt{5x-1}-2\right)=0\)
=>\(\dfrac{3\left(x-1\right)}{\sqrt{3x+1}+2}+2\cdot\dfrac{x+3-4}{\sqrt{x+3}+2}-3\cdot\dfrac{5x-1-4}{\sqrt{5x-1}+2}=0\)
=>\(\left(x-1\right)\left(\dfrac{3}{\sqrt{3x+1}+2}+\dfrac{2}{\sqrt{x+3}+2}-\dfrac{15}{\sqrt{5x-1}+2}\right)=0\)
=>x-1=0
=>x=1
ĐKXĐ: \(x>\dfrac{1}{5}\)
\(1-3x^2< \left(x+2\right)\sqrt[]{5x-1}+5x-1\)
\(\Leftrightarrow3x^2+5x-2+\left(x+2\right)\sqrt{5x-1}\ge0\)
\(\Leftrightarrow\left(x+2\right)\left(3x-1\right)+\left(x+2\right)\sqrt{5x-1}>0\)
\(\Leftrightarrow\left(x+2\right)\left(3x-1+\sqrt{5x-1}\right)>0\)
\(\Leftrightarrow3x-1+\sqrt{5x-1}>0\)
\(\Leftrightarrow\sqrt{5x-1}>1-3x\)
TH1: \(\left\{{}\begin{matrix}x\ge\dfrac{1}{5}\\1-3x< 0\end{matrix}\right.\) \(\Leftrightarrow x>\dfrac{1}{3}\)
TH2: \(\left\{{}\begin{matrix}x\le\dfrac{1}{3}\\5x-1>9x^2-6x+1\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\le\dfrac{1}{3}\\9x^2-11x+2< 0\end{matrix}\right.\) \(\Rightarrow\dfrac{2}{9}< x\le\dfrac{1}{3}\)
Kết luận: \(x>\dfrac{2}{9}\)
ĐKXĐ: \(x\ge1\)
\(\sqrt{5x-1}=\sqrt{3x-2}+\sqrt{x-1}\)
\(\Leftrightarrow5x-1=3x-2+x-1+2\sqrt{\left(3x-2\right)\left(x-1\right)}\)
\(\Leftrightarrow x+2=2\sqrt{\left(3x-2\right)\left(x-1\right)}\)
\(\Leftrightarrow x^2+4x+4=4\left(3x-2\right)\left(x-1\right)\)
\(\Leftrightarrow11x^2-24x+4=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{11}\left(loại\right)\\x=2\end{matrix}\right.\)