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5 tháng 3 2018
b) 52-\(|\)x\(|\)=-80
\(|\)x\(|\)=52-(-80)
\(|\)x\(|\)=52+80
\(|\)x\(|\)=132
Vậy x=-132
29 tháng 3 2018
\(\frac{x+2}{17}+\frac{x+4}{15}+\frac{x+6}{13}=\frac{x+8}{11}+\frac{x+10}{9}+\frac{x+12}{7}\)
\(\Rightarrow\left(\frac{x+2}{17}+1\right)+\left(\frac{x+4}{15}+1\right)+\left(\frac{x+6}{13}+1\right)-\left(\frac{x+8}{11}+1\right)-\left(\frac{x+10}{9}+1\right)-\left(\frac{x+12}{7}+1\right)=0\)
\(\Rightarrow\frac{x+19}{17}+\frac{x+19}{15}+\frac{x+19}{13}-\frac{x+19}{11}-\frac{x+19}{10}-\frac{x+19}{7}=0\)
\(\Rightarrow\left(x+19\right)(\frac{1}{17}+\frac{1}{15}+\frac{1}{13}-\frac{1}{11}-\frac{1}{9}-\frac{1}{7})\)
\(\Rightarrow x+19=0\)\(\left(Vì\frac{1}{17}+\frac{1}{15}+\frac{1}{13}-\frac{1}{11}-\frac{1}{9}-\frac{1}{7}\ne0\right)\)
\(\Rightarrow x=-19\)
TN
28 tháng 3 2018
Ta có : \(\frac{x+2}{17}+\frac{x+4}{15}+\frac{x+6}{13}=\frac{x+8}{11}+\frac{x+10}{9}+\frac{x+12}{7}\)
\(\Rightarrow\left(\frac{x+2}{17}+1\right)+\left(\frac{x+4}{15}+1\right)+\left(\frac{x+6}{13}+1\right)=\left(\frac{x+8}{11}+1\right)+\left(\frac{x+10}{9}+1\right)+\left(\frac{x+12}{7}+1\right)\)
\(\Rightarrow\frac{x+19}{17}+\frac{x+19}{15}+\frac{x+19}{13}-\frac{x+19}{11}-\frac{x+19}{9}-\frac{x+19}{7}=0\)
\(\Rightarrow\left(x+19\right)\left(\frac{1}{17}+\frac{1}{15}+\frac{1}{13}-\frac{1}{11}-\frac{1}{9}-\frac{1}{7}\right)=0\)
\(\Rightarrow x+19=0\Rightarrow x=-19\)
H
1
HN
18 tháng 12 2018
\(a,10+2|x|=2.\left(3^2-1\right)\)
\(\Leftrightarrow10+2|x|=2.\left(9-1\right)\)
\(\Leftrightarrow10+2|x|=16\)
\(\Leftrightarrow2|x|=6\)
\(\Leftrightarrow|x|=3\)
\(\Leftrightarrow\orbr{\begin{cases}x=3\\x=-3\end{cases}}\)
\(b,\left(|3|x+9\right):4=-15\)
\(\Leftrightarrow\frac{3x+9}{4}=-15\)
\(\Leftrightarrow3x+9=-60\)
\(\Leftrightarrow3x=-69,\)
\(\Leftrightarrow x=-23\)
CW
1 tháng 7 2016
1) \(\frac{1}{7}=\frac{8}{-x}\Rightarrow-x=7\cdot8\)
\(-x=56\)
\(x=-56\)
5) \(\left(x-2\frac{1}{4}\right):\left(-\frac{5}{6}\right)=3\)
\(x-\frac{9}{4}=3\cdot\left(-\frac{5}{6}\right)\)
\(x-\frac{9}{4}=-\frac{5}{2}\)
\(x=-\frac{5}{2}+\frac{9}{4}\)
\(x=-\frac{1}{4}\)
6) \(-8\left(4\frac{1}{5}\cdot x+\frac{3}{10}\right)=4\frac{4}{9}\)
\(-8\left(\frac{21}{5}x+\frac{3}{10}\right)=\frac{40}{9}\)
\(\frac{21}{5}x+\frac{3}{10}=\frac{40}{9}:\left(-8\right)\)
\(\frac{21}{5}x+\frac{3}{10}=-\frac{5}{9}\)
\(\frac{21}{5}x=-\frac{5}{9}-\frac{3}{10}\)
\(\frac{21}{5}x=-\frac{77}{90}\)
\(x=-\frac{77}{90}:\frac{21}{5}\)
\(x=-\frac{11}{54}\)
a,\(x^4:9=9\\ \Leftrightarrow\orbr{\begin{cases}x=1\\x=-1\end{cases}}\)
b,\(x^2-30=6\\ \Leftrightarrow x^2=36\Leftrightarrow\orbr{\begin{cases}x=6\\x=-6\end{cases}}\)
c,\(x^2:10=10\Leftrightarrow x^2=\orbr{\begin{cases}x=1\\x=-1\end{cases}}\)
x4 : 9 = 9
x4 = 9 . 9
x4 = 81
x4 = 34
=> x = 3
x2 - 30 = 6
x2 = 6 + 30
x2 = 36
x2 = 62
=> x = 6
x2 : 10 = 10
x2 = 10 . 10
x2 = 100
x2 = 102
=> x = 10