Question

Tìm x biết:

a 1/7< x/35<2/5                           giúp mình v ạ mình đag cần gấp

   b  5/13 <2-x < 5/8

Answer 1

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

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

\(\Rightarrow5< x< 14\)

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

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

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

Answer 2

ai mần tr mình cho tích

Answer 3

a) ta có:\(\dfrac{1}{7}=\dfrac{1.5}{7.5}=\dfrac{5}{35}\);\(\dfrac{2}{5}=\dfrac{2.7}{5.7}=\dfrac{14}{35}\)

\(\Rightarrow x\in\left\{6;7;8;9;10;11;12;13\right\}\)

b)ta có:\(2-x=\dfrac{5}{9};\dfrac{5}{10};\dfrac{5}{11};\dfrac{5}{12}\)

\(\Rightarrow x=2-\dfrac{5}{9};2-\dfrac{5}{10};2-\dfrac{5}{11};2-\dfrac{5}{12}\)

\(\Rightarrow x=\dfrac{13}{9};\dfrac{3}{2};\dfrac{17}{11};\dfrac{19}{12}\)

Answer 4

A) $\genfrac{}{}{0ex}{}{1}{7}<\genfrac{}{}{0ex}{}{x}{35}<\genfrac{}{}{0ex}{}{2}{5}$

$\Rightarrow \genfrac{}{}{0ex}{}{5}{35}<\genfrac{}{}{0ex}{}{x}{35}<\genfrac{}{}{0ex}{}{14}{35}$

$\Rightarrow 5<x<14$

B) 

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