Question

Tìm các số nguyên a sao cho:
-3/8 < a/10 <-3/5
Mong mn giúp đỡ ạ!

Answer 1

\(-\dfrac{3}{8}< \dfrac{a}{10}< -\dfrac{3}{5}\)

\(\Rightarrow-\dfrac{15}{40}< \dfrac{4a}{40}< -\dfrac{24}{40}\)

\(\Rightarrow-15< 4a< -24\)

\(\Rightarrow a=\left\{-4;-5\right\}\)

Answer 2

`-3/8 < a/10 < -3/5`

`=> (-3 xx 5)/(8xx5)<(a xx 4)/(10xx4)<(-3xx8)/(5xx8)`
`=> -15/40 < 4a/40<-24/40`

`=> -15<4a<-24`

`=> 4a` ∈ `{-16 ; -17 ; -18 ; -19 ; -20 ; -21 ;- 22 ; -23 .}`

`=>`a ∈ `{-4 ; -17/4 ; -9/2 ; -19/4 ; -5 ; -21/4 ; -11/2 ; -23/4}`

Vì `a` là số nguyên nên :

`a` ∈`{-4 ; -5}`

vậy `a` ∈`{-4 ; -5}`