$\text { Đáp án: }$
` a) `
` 4 < x < 13/3 ` $\text { (đk: x ∈ Z) }$
` => 4 < x < 4,33... `
` => x ∈ ∅ `
` b) `
` –4 < x < –15/4 ` $\text { (đk: x ∈ Z) }$
` => –4 < x < –3,75 `
` => x ∈ ∅ `
` c) `
` –2 < x < –1 ` $\text { (đk: x ∈ Z) }$
` => x ∈ ∅ `
` d) `
` 0 < x < 1/2 ` $\text { (đk: x ∈ Z) }$
` => 0 < x < 0,5 `
` => x ∈ ∅ `