Răspuns :
[tex]\it \dfrac{^{2)}2}{\ 5}=\dfrac{x}{10} \Rightarrow \dfrac{4}{10}=\dfrac{x}{10} \Rightarrow x=4\\ \\ \\ \dfrac{2}{5}=\dfrac{x}{10} \Rightarrow x=\dfrac{2\cdot10}{5}=\dfrac{20}{5}=4[/tex]
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[tex]\it \dfrac{6}{x}=\dfrac{4}{5} \Rightarrow x=\dfrac{6\cdot5}{4}=\dfrac{\ 30^{(2}}{4}=\dfrac{15}{2}=7,5[/tex]