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b) \(\left|5x-3\right|-x=7\)
\(\Rightarrow\left|5x-3\right|=7+x\)
\(\Rightarrow\orbr{\begin{cases}5x-3=7+x\\5x-3=-\left(7+x\right)\end{cases}\Rightarrow\orbr{\begin{cases}5x-3=7+x\\5x-3=-7-x\end{cases}\Rightarrow}\orbr{\begin{cases}5x-x=7+3\\5x+x=-7+3\end{cases}}}\)
\(\Rightarrow\orbr{\begin{cases}4x=10\\6x=-4\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{5}{2}\\x=-\frac{2}{3}\end{cases}}}\)
Vậy ....................
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https://h.vn/hoi-dap/question/394208.html
~ Học tốt ~
a) x² - 2 = 0
x² = 2
x = -√2 (loại) hoặc x = √2 (loại)
Vậy không tìm được x Q thỏa mãn đề bài
b) x² + 7/4 = 23/4
x² = 23/4 - 7/4
x² = 4
x = 2 (nhận) hoặc x = -2 (nhận)
Vậy x = -2; x = 2
c) (x - 1)² = 0
x - 1 = 0
x = 1 (nhận)
Vậy x = 1
Bài 3:
a: \(\Leftrightarrow\left[{}\begin{matrix}2x-3=0\\\dfrac{3}{4}x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=-\dfrac{4}{3}\end{matrix}\right.\)
b: \(\Leftrightarrow\left\{{}\begin{matrix}3x+2>0\\\dfrac{2}{3}x-5< 0\end{matrix}\right.\Leftrightarrow-\dfrac{2}{3}< x< \dfrac{15}{2}\)
c: \(\Leftrightarrow\left[{}\begin{matrix}\dfrac{3}{4}x+2=0\\\dfrac{2}{5}x-6=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x\cdot\dfrac{3}{4}=-2\\\dfrac{2}{5}x=6\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{8}{3}\\x=6:\dfrac{2}{5}=15\end{matrix}\right.\)
1a) \(\left|\frac{3}{2}x+\frac{1}{2}\right|=\left|4x-1\right|\)
=> \(\orbr{\begin{cases}\frac{3}{2}x+\frac{1}{2}=4x-1\\\frac{3}{2}x+\frac{1}{2}=1-4x\end{cases}}\)
=> \(\orbr{\begin{cases}-\frac{5}{2}x=-\frac{3}{2}\\\frac{11}{2}x=\frac{1}{2}\end{cases}}\)
=> \(\orbr{\begin{cases}x=\frac{5}{3}\\x=\frac{1}{11}\end{cases}}\)
b) \(\left|\frac{5}{4}x-\frac{7}{2}\right|-\left|\frac{5}{8}x+\frac{3}{5}\right|=0\)
=>\(\left|\frac{5}{4}x-\frac{7}{2}\right|=\left|\frac{5}{8}x+\frac{3}{5}\right|\)
=> \(\orbr{\begin{cases}\frac{5}{4}x-\frac{7}{2}=\frac{5}{8}x+\frac{3}{5}\\\frac{5}{4}x-\frac{7}{2}=-\frac{5}{8}x-\frac{3}{5}\end{cases}}\)
=> \(\orbr{\begin{cases}\frac{5}{8}x=\frac{41}{10}\\\frac{15}{8}x=\frac{29}{10}\end{cases}}\)
=> \(\orbr{\begin{cases}x=\frac{164}{25}\\x=\frac{116}{75}\end{cases}}\)
c) TT
a, \(\left|\frac{3}{2}x+\frac{1}{2}\right|=\left|4x-1\right|\)
=> \(\orbr{\begin{cases}\frac{3}{2}x+\frac{1}{2}=4x-1\\-\frac{3}{2}x-\frac{1}{2}=4x-1\end{cases}}\)
=> \(\orbr{\begin{cases}\frac{3}{2}x+\frac{1}{2}-4x=-1\\-\frac{3}{2}x-\frac{1}{2}-4x=-1\end{cases}}\)
=> \(\orbr{\begin{cases}x=\frac{3}{5}\\x=\frac{1}{11}\end{cases}}\)
\(b,\left|\frac{5}{4}x-\frac{7}{2}\right|-\left|\frac{5}{8}x+\frac{3}{5}\right|=0\)
=> \(\left|\frac{5}{4}x-\frac{7}{2}\right|-0=\left|\frac{5}{8}x+\frac{3}{5}\right|\)
=> \(\frac{\left|5x-14\right|}{4}=\frac{\left|25x+24\right|}{40}\)
=> \(\frac{10(\left|5x-14\right|)}{40}=\frac{\left|25x+24\right|}{40}\)
=> \(\left|50x-140\right|=\left|25x+24\right|\)
=> \(\orbr{\begin{cases}50x-140=25x+24\\-50x+140=25x+24\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{164}{25}\\x=\frac{116}{75}\end{cases}}\)
c, \(\left|\frac{7}{5}x+\frac{2}{3}\right|=\left|\frac{4}{3}x-\frac{1}{4}\right|\)
=> \(\orbr{\begin{cases}\frac{7}{5}x+\frac{2}{3}=\frac{4}{3}x-\frac{1}{4}\\-\frac{7}{5}x-\frac{2}{3}=\frac{4}{3}x-\frac{1}{4}\end{cases}}\)
=> \(\orbr{\begin{cases}x=-\frac{55}{4}\\x=-\frac{25}{164}\end{cases}}\)
Bài 2 : a. |2x - 5| = x + 1
TH1 : 2x - 5 = x + 1
=> 2x - 5 - x = 1
=> 2x - x - 5 = 1
=> 2x - x = 6
=> x = 6
TH2 : -2x + 5 = x + 1
=> -2x + 5 - x = 1
=> -2x - x + 5 = 1
=> -3x = -4
=> x = 4/3
Ba bài còn lại tương tự
\(a,\left(\frac{1}{7}x-\frac{2}{7}\right)\left(-\frac{1}{5}x+\frac{3}{5}\right)\left(\frac{1}{3}x+\frac{4}{3}\right)=0\)
TH1 : \(\frac{1}{7}x-\frac{2}{7}=0\Rightarrow\frac{x-2}{7}=0\Rightarrow x-2=0\Leftrightarrow x=2\)
TH2 : \(-\frac{1}{5}x+\frac{3}{5}=0\Rightarrow\frac{-x+3}{5}=0\Rightarrow-x+3=0\Leftrightarrow x=3\)
TH3 : \(\frac{1}{3}x+\frac{4}{3}=0\Rightarrow\frac{x+4}{3}=0\Rightarrow x+4=0\Leftrightarrow x=-4\)
\(\Rightarrow x\in\left\{2;3;-4\right\}\)
\(b,\frac{1}{6}x+\frac{1}{10}x-\frac{4}{15}x+1=0\)
\(\Rightarrow\frac{5}{30}x+\frac{3}{30}x-\frac{8}{30}x+1=0\)
\(\Rightarrow\frac{5x+3x-8x}{30}+1=0\)
\(\Rightarrow1=0\)( vô lý )\(\Rightarrow x\in\varnothing\)
bạn ơi trả lời được câu này kông
( x + 1 ) + ( x - 3 ) + ( x + 5 ) + ............ + ( x +9) = 35
`#3107.101107`
`1/2x + 4/5 = 2x - 8/5`
`=> 1/2x - 2x = -4/5 - 8/5`
`=> -3/2x = -12/5`
`=> x = -12/5 \div (-3/2)`
`=> x = 8/5`
Vậy, `x = 8/5`
_____
`\sqrt{x} = 5`
`=> x = 5^2`
`=> x = 25`
Vậy, `x = 25`
___
`x^2 = 3`
`=> x^2 = (+-\sqrt{3})^2`
`=> x = +- \sqrt{3}`
Vậy, `x \in {-\sqrt{3}; \sqrt{3}}.`
\(a,\frac{1}{6}x+\frac{1}{10}x-\frac{4}{15}x+1=0\)
\(\Leftrightarrow\left[\frac{1}{6}+\frac{1}{10}-\frac{4}{15}\right]x=-1\)
\(\Leftrightarrow0x=-1\Leftrightarrow x\in\varnothing\)
\(b,\left|x\cdot\left[x^2-\frac{5}{4}\right]\right|=x\)
Vì vế trái \(\left|x\left[x^2-\frac{5}{4}\right]\right|\ge0\)với mọi x nên vế phải \(x\ge0\)
Ta có : \(x\left|x^2-\frac{5}{4}\right|=x\)vì \(x\ge0\)
Nếu x = 0 thì \(0\left|0^2-\frac{5}{4}\right|=0\)đúng
Nếu \(x\ne0\)thì ta có \(\left|x^2-\frac{5}{4}\right|=1\Leftrightarrow x^2-\frac{5}{4}=\pm1\Leftrightarrow\orbr{\begin{cases}x=\frac{3}{2}\\x=\frac{1}{2}\end{cases}}\)
a) \(\frac{1}{6}x+\frac{1}{10}x-\frac{4}{15}x+1=0\)
=> \(\left(\frac{1}{6}+\frac{1}{10}-\frac{4}{15}\right)x+1=0\)
=> \(0x+1=0\)
=> \(1=0\)(vô lí)
b) |x . (x2 - 5/4)| = x
TH1: \(x.\left(x^2-\frac{5}{4}\right)=x\)
=> \(x^3-\frac{5}{4}x-x=0\)
=> \(x^3-\frac{9}{4}x=0\)
=> \(x\left(x^2-\frac{9}{4}\right)=0\)
=> \(\orbr{\begin{cases}x=0\\x^2-\frac{9}{4}=0\end{cases}}\)
=> \(\orbr{\begin{cases}x=0\\x^2=\left(\frac{3}{2}\right)^2\end{cases}}\)
=> \(\orbr{\begin{cases}x=0\\x=\pm\frac{3}{2}\end{cases}}\)
TH2: \(x\left(x^2-\frac{5}{4}\right)=-x\)
=> \(x^3-\frac{5}{4}x+x=0\)
=> \(x^3-\frac{1}{4}x=0\)
=> \(x\left(x^2-\frac{1}{4}\right)=0\)
=> \(\orbr{\begin{cases}x=0\\x^2-\frac{1}{4}=0\end{cases}}\)
=> \(\orbr{\begin{cases}x=0\\x^2=\left(\frac{1}{2}\right)^2\end{cases}}\)
=> \(\orbr{\begin{cases}x=0\\x=\pm\frac{1}{2}\end{cases}}\)
Do |x.(x2 - 5/4)| \(\ge\)0 => x\(\ge\)0 => x thuộc {0; 1/2; 3/2}
\(a,\frac{x+5}{2010}+\frac{x+6}{2009}+\frac{x+7}{2008}=-3\)
\(\Rightarrow\left(\frac{x+5}{2010}+1\right)+\left(\frac{x+6}{2009}+1\right)+\left(\frac{x+7}{2008}+1\right)=0\)
\(\Rightarrow\frac{x+2016}{2010}+\frac{x+2016}{2009}+\frac{x+2006}{2008}=0\)
chỉ bt lm v thoi "(
a) \(\frac{x+5}{2010}+\frac{x+6}{2009}+\frac{x+7}{2008}=-3\)
<=> \(\frac{x+5}{2010}+1+\frac{x+6}{2009}+1+\frac{x+7}{2008}+1=0\)
<=> \(\frac{x+2015}{2010}+\frac{x+2015}{2009}+\frac{x+2015}{2008}=0\)
<=> \(\left(x+2015\right)\left(\frac{1}{2010}+\frac{1}{2009}+\frac{1}{2008}\right)=0\)
<=> \(x+2015=0\) (do 1/2010 + 1/2009 + 1/2008 # 0 )
<=> \(x=-2015\)
Vậy...
b) mạo phép chỉnh đề
\(\frac{x+2}{327}+\frac{x+3}{326}+\frac{x+4}{325}+\frac{x+344}{5}=0\)
<=> \(\frac{x+2}{327}+1+\frac{x+3}{326}+1+\frac{x+4}{325}+1+\frac{x+344}{5}-3=0\)
<=> \(\frac{x+329}{327}+\frac{x+329}{326}+\frac{x+329}{325}+\frac{x+329}{5}=0\)
làm tương tự a
a)
| x | + | x + 2 | = 0
mà GTTĐ luôn lớn hơn hoặc bằng 0
+) x = 0
+) x + 2 = 0
=> x = -2
b)
| x ( x^2 - 5/4 ) | = x
+) x ( x^2 - 5/4 ) = x
=> x^2 - 5/4 = 1
=> x^2 = 9/4
=> x = { 3/2; -3/2 }
+) x ( x^2 - 5/4 ) = -x
=> x^2 - 5/4 = -1
=> x^2 = 1/4
=> x = { 1/2; -1/2 }
Vậy,........
a, x= -2.
b,x= 1/2 hoặc -1/2.
K mk nha.