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\(a,\Rightarrow\left(35x+3\right)\cdot19=152\\ \Rightarrow35x+3=8\\ \Rightarrow x=\dfrac{1}{7}\\ b,\Rightarrow3\left(x+7\right)=42\\ \Rightarrow x+7=14\Rightarrow x=7\\ c,\Rightarrow3\left(x+1\right)=48\\ \Rightarrow x+1=16\Rightarrow x=15\\ d,\Rightarrow120-5x+100\cdot2:5=4\cdot15\\ \Rightarrow120-5x+40=60\\ \Rightarrow5x=100\Rightarrow x=20\\ e,\Rightarrow4x-10=30\\ \Rightarrow4x=40\\ \Rightarrow x=10\\ g,\Rightarrow10x+10=70\\ \Rightarrow10x=60\\ \Rightarrow x=6\)
a) \(\frac{3}{2}-\left(x-\frac{7}{3}\right)=\left|-\frac{3}{4}-\frac{9}{8}\right|\)
=> \(\frac{3}{2}-x+\frac{7}{3}=\left|-\frac{15}{8}\right|\)
=> \(\frac{3}{2}-x+\frac{7}{3}=\frac{15}{8}\)
=> \(\frac{3}{2}-x=-\frac{11}{24}\)
=> \(x=\frac{47}{24}\)
b) \(\frac{5}{2}-\left(\frac{3}{2}-\frac{7}{3}+x\right)=\frac{8}{15}-\left(\frac{1}{4}-\frac{7}{10}\right)\)
=> \(\frac{5}{2}-\frac{3}{2}+\frac{7}{3}-x=\frac{8}{15}-\left(-\frac{9}{20}\right)\)
=> \(\frac{10}{3}-x=\frac{59}{60}\)
=> \(x=\frac{10}{3}-\frac{59}{60}=\frac{47}{20}\)
c) \(2\left(\frac{3}{4}-5x\right)=\frac{4}{5}-3x\)
=> \(\frac{3}{2}-10x-\frac{4}{5}+3x=0\)
=> \(\left(\frac{3}{2}-\frac{4}{5}\right)+\left(-10x+3x\right)=0\)
=> \(\frac{7}{10}-7x=0\)
=> \(7x=\frac{7}{10}\)
=> x = 1/10
a) Ta có: \(\dfrac{x}{3}=\dfrac{7}{25}+\dfrac{-1}{5}\)
\(\Leftrightarrow\dfrac{x}{3}=\dfrac{7}{25}+\dfrac{-5}{25}=\dfrac{2}{25}\)
hay \(x=\dfrac{6}{25}\)
Vậy: \(x=\dfrac{6}{25}\)
b) Ta có: \(\dfrac{4}{9}+\dfrac{x}{5}=\dfrac{5}{11}\)
\(\Leftrightarrow\dfrac{x}{5}=\dfrac{5}{11}-\dfrac{4}{9}=\dfrac{45}{99}-\dfrac{44}{99}=\dfrac{1}{99}\)
hay \(x=\dfrac{5}{99}\)
Vậy: \(x=\dfrac{5}{99}\)
Câu 1:
Đặt \(A=\frac{n-8}{n+3}\)
Ta có:\(A=\frac{n-8}{n+3}=\frac{n+3-11}{n+3}=1-\frac{11}{n+3}\)
Để A nguyên thì 11 chia hết cho n+3 hay \(\left(n+3\right)\inƯ\left(11\right)\)
Vậy Ư(11) là:[1,-1,11,-11]
Do đó ta có bảng sau :
| n+3 | -11 | -1 | 1 | 11 |
| n | -14 | -4 | -2 | 8 |
Vậy phân số là một số nguyên thì n=-14;-4;-2;8
2. a) 3 ( x-5) = 2(x-11)
3x - 15 = 2x - 22
3x - 2x = -22 + 15
x = -7
b) 0.27 + \(\frac{1}{2}\) < x% < 1 -20%
1.25 < x % < 0.8
còn lại mình ko biết
c) \(\frac{x}{2}\)- \(\frac{3}{10}\) = \(\frac{1}{5}\)
\(\frac{x}{2}\) = \(\frac{1}{5}\) + \(\frac{3}{10}\)
\(\frac{x}{2}\) = \(\frac{2}{10}\)+\(\frac{3}{10}\)
\(\frac{x}{2}\) = \(\frac{1}{2}\)
=> x = 1
\(\frac{x}{5}-\frac{3}{7}=\frac{10}{13}\)
\(\Rightarrow\frac{91x}{455}-\frac{195}{455}=\frac{350}{455}\)
\(\Rightarrow91x-195=350\)
\(\Rightarrow91x=545\)
\(\Rightarrow x=\frac{545}{91}\)
\(\frac{-3x}{4}+\frac{1}{3}=\frac{11}{5}\)
\(\Rightarrow\frac{-45x}{60}+\frac{20}{60}=\frac{132}{60}\)
\(\Rightarrow-45x+20=132\)
\(\Rightarrow-45x=112\)
\(\Rightarrow x=-\frac{112}{45}\)