Question

tìm a thuộc Z , biết :

\(\dfrac{-5}{12}\)<\(\dfrac{a}{5}\)<\(\dfrac{1}{4}\)

Answer 1

\(\dfrac{-5}{12}< \dfrac{a}{5}< \dfrac{1}{4}\)

\(\Leftrightarrow\dfrac{-25}{60}< \dfrac{12a}{60}< \dfrac{15}{60}\)

\(\Rightarrow-25< 12a< 15\) mà \(a\in Z\)

\(\Rightarrow a\in\left\{-2;0;1\right\}\)

Answer 2

tìm a thuộc Z , biết :

\(\dfrac{-5}{12}< \dfrac{a}{5}< \dfrac{1}{4}\)

Ta lấy mẫu chung là 60

\(\Rightarrow\dfrac{-5.5}{12.5}< \dfrac{12.a}{5.12}< \dfrac{1.15}{4.15}\)

\(\Rightarrow\dfrac{-25}{60}< \dfrac{12.a}{60}< \dfrac{15}{60}\)

\(\Rightarrow\) -25<12a<15

\(\Rightarrow a\in\left\{-2,0.1\right\}\)