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Bài 1:
\(=\dfrac{-3-39}{42}+\dfrac{-6-11}{17}-\dfrac{1}{6}=-\dfrac{119}{48}\)
Bài 2:
=>x:5=-13/20
hay x=-65/20=-13/4
a) \(x-2=-6\)
\(x=-6+2\)
\(x=-4\)
b) \(15-\left(x-7\right)=-21\)
\(x-7=36\)
\(x=43\)
c) \(4.\left(3x-4\right)-2=18\)
\(4\left(3x-4\right)=20\)
\(3x-4=5\)
\(3x=9\)
\(x=3\)
d) \(\left(3x-6\right)+3=32\)
\(3x-6=29\)
\(3x=29+6\)
\(3x=35\)
\(x=\frac{35}{3}\)
e) \(\left(3x-6\right).3=32\)
\(3x-6=\frac{32}{3}\)
\(3x=\frac{32}{3}+6\)
\(3x=\frac{50}{3}\)
\(x=\frac{50}{9}\)
f) \(\left(3x-6\right):3=32\)
\(3x-6=96\)
\(3x=102\)
\(x=34\)
g) \(\left(3x-6\right)-3=32\)
\(3x-6=35\)
\(3x=41\)
\(x=\frac{41}{3}\)
h) \(\left(3x-2^4\right).7^3=2.7^4\)
\(\left(3x-2^4\right)=2.7=14\)
\(\left(3x-16\right)=14\)
\(3x=14+16=30\)
\(x=10\)
i) \(\left|x\right|=\left|-7\right|\)
\(\left|x\right|=7\)
\(\Rightarrow\orbr{\begin{cases}x=7\\x=-7\end{cases}}\)
k) \(\left|x+1\right|=2\)
\(\Rightarrow\orbr{\begin{cases}x+1=2\\x+1=-2\end{cases}\Rightarrow\orbr{\begin{cases}x=1\\x=-3\end{cases}}}\)
l) \(\left|x-2\right|=3\)
\(\Rightarrow\orbr{\begin{cases}x-2=3\\x-2=-3\end{cases}\Rightarrow\orbr{\begin{cases}x=5\\x=-1\end{cases}}}\)
m) \(x+\left|-2\right|=0\)
\(x+2=0\)
\(x=-2\)
o) \(72-3\left|x+1\right|=9\)
\(3\left|x-1\right|=63\)
\(\left|x-1\right|=21\)
\(\Rightarrow\orbr{\begin{cases}x-1=21\\x-1=-21\end{cases}\Rightarrow\orbr{\begin{cases}x=22\\x=-20\end{cases}}}\)
p) Ta có: \(\left|x-1\right|=3\)
\(\Rightarrow\orbr{\begin{cases}x-1=3\\x-1=-3\end{cases}}\)
mà \(x+1< 0\)
\(\Rightarrow x-1=-3\)
\(\Rightarrow x=-2\)
q) \(\left(x-2\right)\left(x+4\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-2=0\\x+4=0\end{cases}\Rightarrow\orbr{\begin{cases}x=2\\x=-4\end{cases}}}\)
hok tốt!!
a: \(=3\cdot\left(\dfrac{1}{4}-\dfrac{6}{7}+\dfrac{8}{21}\right)\)
\(=3\cdot\left(\dfrac{21}{84}-\dfrac{72}{84}+\dfrac{32}{84}\right)\)
\(=\dfrac{-19}{28}\)
b: \(=\dfrac{-2}{3}\left(\dfrac{1}{9}-\dfrac{1}{6}-\dfrac{1}{11}\right)\)
\(=\dfrac{-2}{3}\cdot\dfrac{-29}{198}=\dfrac{29}{99\cdot3}=\dfrac{29}{297}\)
c: \(=\dfrac{-3}{7}+\dfrac{4}{25}+\dfrac{5}{16}+\dfrac{3}{16}\)
\(=\dfrac{-75+28}{175}+\dfrac{1}{2}\)
\(=\dfrac{-47}{175}+\dfrac{1}{2}=\dfrac{-94+175}{350}=\dfrac{81}{350}\)
d: \(=\dfrac{-4}{9}\cdot\left(\dfrac{1}{26}-\dfrac{1}{2}-\dfrac{1}{8}\right)\)
\(=\dfrac{-4}{9}\cdot\dfrac{-61}{104}=\dfrac{61}{26\cdot9}=\dfrac{61}{234}\)
Bài 1:
\(=\dfrac{-3-39}{32}+\dfrac{-6-11}{17}+\dfrac{-1}{6}=-\dfrac{21}{16}+\dfrac{-1}{6}-1=-\dfrac{119}{48}\)
Bài 2:
\(\Leftrightarrow x:5=-\dfrac{13}{20}\)
hay x=-13/4
TL:
a.\(2^6.2^n=2^{11}\)
\(2^{6+n}=2^{11}\)
\(\Rightarrow n=5\)
b. \(3^7:3^n=3^4\)
\(3^{7-n}=3^4\)
\(\Rightarrow n=3\)
c.\(2^n.32=2^{10}\)
\(2^{n+5}=2^{10}\)
\(\Rightarrow n=5\)