Question

Tìm x, biết: 1-\(\dfrac{2}{3}\)<\(\dfrac{x}{3}< 3\dfrac{1}{3}\)

Answer 1

ta có: \(\dfrac{x}{3}\) > \(1-\dfrac{2}{3}\) và \(\dfrac{x}{3}\) < \(3\dfrac{1}{3}\)

\(\dfrac{x}{3}\)>\(1-\dfrac{2}{3}\) => \(\dfrac{x}{3}\)>\(\dfrac{1}{3}\) => x>1

\(\dfrac{x}{3}\)<\(3\dfrac{1}{3}\) => \(\dfrac{x}{3}\)<\(\dfrac{10}{3}\) => x<10

=> S= {x|1<x<10}

Answer 2

1-\(\dfrac{2}{3}\)<\(\dfrac{x}{3}\)

⇒ \(\dfrac{1}{3}\)< \(\dfrac{x}{3}\)< \(\dfrac{10}{3}\)

⇒ 1 < x < 10

⇒ x ∈ { 2 ; 3 ; 4 ; 5 ; 6 ; 7 ; 8 ; 9 }

Answer 3

https://i.imgur.com/jKgopuD.jpg