Răspuns :
aducem la acelasi numitor
18 < 4x+8 < 27 |-8
10 < 4x < 19 |:4
2,5 < x < 4,75
x∈N ⇒x∈(2;4) ⇔x∈{3}
18 < 4x+8 < 27 |-8
10 < 4x < 19 |:4
2,5 < x < 4,75
x∈N ⇒x∈(2;4) ⇔x∈{3}
[tex]\dfrac32<x+\dfrac23<\dfrac94\ scadem \ \dfrac23\Rightarrow\dfrac32-\dfrac23<x<\dfrac94-\dfrac23\Rightarrow\dfrac56<x<\dfrac{19}{12}\Rightarrow [/tex]
[tex]\Rightarrow0,...<x<1,...\Rightarrow x=1[/tex]
[tex]\Rightarrow0,...<x<1,...\Rightarrow x=1[/tex]