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Khách

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12 tháng 8 2023

a) \(\dfrac{1}{7}< \dfrac{x}{35}< \dfrac{2}{5}\)

\(\Rightarrow\dfrac{5}{35}< \dfrac{x}{35}< \dfrac{14}{35}\)

\(\Rightarrow5< x< 14\)

b) \(\dfrac{5}{13}< 2-x< \dfrac{5}{8}\)

\(\Rightarrow2-\dfrac{5}{8}< x< 2-\dfrac{5}{13}\)

\(\Rightarrow\dfrac{11}{8}< x< \dfrac{21}{13}\)

12 tháng 8 2023

ai mần tr mình cho tích

19 tháng 1 2019

\(2x+4⋮x-1\Rightarrow2\left(x-1\right)+6⋮x-1\)

\(\Rightarrow6⋮x-1\Rightarrow x-1\inƯ\left(6\right)=\left\{\pm1;\pm2;\pm3;\pm6\right\}\)

\(\Rightarrow x\in\left\{2;0;3;-1;4;-2;7;-5\right\}\)

Vậy...........................................

\(2x^2+\left(-3\right)^2=41\)

\(\Rightarrow2x^2=41-9=32\)

\(\Rightarrow x^2=16\)

\(\Rightarrow x=\pm4\)

\(2\left(x-5\right)-3\left(x+7\right)=14\)

\(\Rightarrow2x-10-3x-21=14\)

\(\Rightarrow2x-3x=14+21+10\)

\(\Rightarrow-x=45\Rightarrow x=-45\)

\(-7\left(5-x\right)-2\left(x-10\right)=15\)

\(\Rightarrow-35+x-2x+20=15\)

\(\Rightarrow x-2x=15-20+35\)

\(\Rightarrow-x=30\Rightarrow x=-30\)

30 tháng 5 2015

a) \(\frac{-8}{3}+\frac{7}{5}+\frac{-71}{15}\)\(x\) < \(\frac{-13}{7}+\frac{19}{14}+\frac{-7}{2}\)

Ta có: \(\frac{-8}{3}+\frac{7}{5}+\frac{-71}{15}\)

=\(\frac{-40}{15}+\frac{21}{15}+\frac{-71}{15}\)

=\(\frac{-90}{15}\)

=\(-6\)

Ta có: \(\frac{-13}{7}+\frac{19}{14}+\frac{-7}{2}\)

=\(\frac{-26}{14}+\frac{19}{14}+\frac{-49}{14}\)

=\(\frac{-56}{14}\)

=\(-4\)

=> \(-6\)\(x\)<\(-4\)

=> \(x=-5\)

 

b)\(\frac{5}{17}+\frac{-4}{9}+\frac{-20}{31}+\frac{12}{17}+\frac{-11}{31}\)\(\frac{x}{9}\)<\(\frac{-3}{7}+\frac{7}{15}+\frac{4}{-7}+\frac{8}{15}+\frac{2}{3}\)

Ta có: \(\frac{5}{17}+\frac{-4}{9}+\frac{-20}{31}+\frac{12}{17}+\frac{-11}{31}\)

=\(\left(\frac{5}{17}+\frac{12}{17}\right)+\left(\frac{-20}{31}+\frac{-11}{31}\right)+\frac{-4}{9}\)

=\(1+\left(-1\right)+\frac{-4}{9}\)

=\(0+\frac{-4}{9}\)

=\(\frac{-4}{9}\)

Ta có: \(\frac{-3}{7}+\frac{7}{15}+\frac{4}{-7}+\frac{8}{15}+\frac{2}{3}\)

=\(\frac{-3}{7}+\frac{7}{15}+\frac{-4}{7}+\frac{8}{15}+\frac{2}{3}\)

=\(\left(\frac{-3}{7}+\frac{-4}{7}\right)+\left(\frac{7}{15}+\frac{8}{15}\right)+\frac{2}{3}\)

=\(\left(-1\right)+1+\frac{2}{3}\)

=\(0+\frac{2}{3}\)

=\(\frac{2}{3}\)

=> \(\frac{-4}{9}\)\(\frac{x}{9}\)<\(\frac{2}{3}\)

=

=> \(\frac{-4}{9}\)<\(\frac{x}{9}\)<\(\frac{6}{9}\)

=> \(-4\)\(x\)<\(6\)

=>\(x\in\left\{-3;-2;-1;0;1;2;3;4;5\right\}\)

rtgnthmryjm

10 tháng 3 2016

a) \(\frac{-5}{17}+\frac{3}{17}=\frac{-2}{17}\le\frac{x}{17}<\frac{13}{17}+\frac{-11}{17}=\frac{2}{17}\)

=> x E -1;0;1

b)\(\frac{5}{6}+\frac{-7}{8}=\frac{40}{48}+\frac{-42}{48}=\frac{-2}{48}\le\frac{x}{24}\le\frac{-5}{12}+\frac{5}{8}=\frac{-40}{96}+\frac{60}{96}=\frac{20}{96}=\frac{5}{24}\)

=>-2/48=-1/24

=> x E 0;1;2;3;4;5