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a) A = \(\dfrac{6n+7}{2n+3}\) = \(\dfrac{6n+9}{2n+3}\) − \(\dfrac{2}{2n+3}\) nguyên
⇔ 2n + 3 ∈ Ư(2) = {-2; -1; 1; 2}
⇔ 2n ∈ {-5; -4; -2; -1}
Vì n nguyên nên n ∈ {-2; -1}
\(a,\Leftrightarrow-\dfrac{1}{2}x=\dfrac{1}{4}\Leftrightarrow x=-\dfrac{1}{2}\\ b,\Leftrightarrow\dfrac{1}{6}:x=\dfrac{1}{2}+\dfrac{1}{3}=\dfrac{5}{6}\Leftrightarrow x=\dfrac{1}{6}:\dfrac{5}{6}=\dfrac{1}{5}\\ c,\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{5}=3\\x+\dfrac{1}{5}=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{14}{5}\\x=-\dfrac{16}{5}\end{matrix}\right.\)
\(d,\Leftrightarrow\left(x+\dfrac{1}{2}\right)^2=\dfrac{22}{9}-\dfrac{7}{3}=\dfrac{1}{9}\\ \Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=\dfrac{1}{3}\\x+\dfrac{1}{2}=-\dfrac{1}{3}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{6}\\x=-\dfrac{5}{6}\end{matrix}\right.\\ e,\Leftrightarrow2\left|x\right|=2-\dfrac{1}{2}=\dfrac{3}{2}\\ \Leftrightarrow\left[{}\begin{matrix}2x=\dfrac{3}{2}\\2x=-\dfrac{3}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{4}\\x=-\dfrac{3}{4}\end{matrix}\right.\)
\(f,\Leftrightarrow\left|x+\dfrac{1}{2}\right|=1+\dfrac{1}{6}=\dfrac{7}{6}\\ \Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=\dfrac{7}{6}\\x+\dfrac{1}{2}=-\dfrac{7}{6}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{3}\\x=-\dfrac{5}{3}\end{matrix}\right.\)
e: ta có: \(2\left|x\right|+\dfrac{1}{2}=2\)
\(\Leftrightarrow2\left|x\right|=\dfrac{3}{2}\)
\(\Leftrightarrow\left|x\right|=\dfrac{3}{4}\)
hay \(x\in\left\{\dfrac{3}{4};-\dfrac{3}{4}\right\}\)
\(a,\left|x-1,7\right|=6,5\)\(\Rightarrow\orbr{\begin{cases}X-1,7=6,5\\x-1,7=-6,5\end{cases}\Rightarrow\orbr{\begin{cases}x=8,2\\x=-4,8\end{cases}}}\)
1. Tìm X
a. / X - 1,7 / = 6,5
\(\Rightarrow\)X - 1,7 = 6,5 hay X - 1,7 = - 6,5
X = 6,5 + 1,7 hay X = -6,5 + 1,7
X = 8,2 X = -4,8
Vậy X = 8,2 hay X = -4,8
b. / 2X - 1,5 / - 2,3 = 1,8
/ 2X - 1,5 / = 1,8 + 2,3
/ 2X - 1,5 / = 4,1
\(\Rightarrow\)2X - 1,5 = 4,1 hay 2X - 1,5 = -4,1
2X = 4,1 + 1,5 hay 2X = -4,1 + 1,5
2X = 5,6 2X = -2,6
X = 5,6 : 2 X = -2,6 : 2
X = 2,8 X = -1,3
Vậy X = 2,8 hay X = -1,3
c. / X - \(\frac{3}{4}\) / - \(\frac{5}{6}\)= \(\frac{1}{2}\)
/ X - \(\frac{3}{4}\)/ = \(\frac{1}{2}+\frac{5}{6}\)
/ X - \(\frac{3}{4}\)/ = \(\frac{4}{3}\)
\(\Rightarrow\)X - \(\frac{3}{4}\)= \(\frac{4}{3}\) hay X - \(\frac{3}{4}\)= \(\frac{-4}{3}\)
X = \(\frac{4}{3}+\frac{3}{4}\)hay X = \(\frac{-4}{3}+\frac{3}{4}\)
X = \(\frac{25}{12}\) hay X = \(\frac{-7}{12}\)
Vậy X = \(\frac{25}{12}\)hay X = \(\frac{-7}{12}\)
a, \(\frac{8}{2^n}=2\Rightarrow2.2^n=8\)
\(\Rightarrow2^{n+1}=2^3\)
\(\Rightarrow n+1=3\)
\(\Rightarrow n=2\)
d,\(\left(2n-3\right)^2=9\)
\(\left(2n-3\right)^2=3^2\)
\(\Rightarrow\orbr{\begin{cases}2n-3=-3\\2n-3=3\end{cases}\Rightarrow\orbr{\begin{cases}2n=-3+3\\2n=3+3\end{cases}\Rightarrow}\orbr{\begin{cases}2n=0\\2n=6\end{cases}\Rightarrow}\orbr{\begin{cases}n=0\\n=3\end{cases}}}\)
Vậy n=0; n= 3
cau hoi ban can co the o day https://lazi.vn/edu/exercise/tinh-h-a-1-1-2-2-1-1-3-2-1-1-n-2
a) ( x - 2/9 )3 = ( 2/3 ) 6
=> ( x - 2/9 )3 = (4/9 )3
=> x - 2/9 = 4/9
=> x = 4/9 - 2/9
=> x = 2/9
Tìm x
a) ( x - 2/9 )3 = ( 2/3 ) 6
b) ( 8x - 1 ) 2n + 1 = 5 2n + 1
a) ( x - 2/9 )3 = ( 2/3 ) 6
=> ( x - 2/9 )3 = (4/9 )3
=> x - 2/9 = 4/9
=> x = 4/9 - 2/9
=> x = 2/9