Question

tìm x biết 

1-2/x< hoặc bằng 1/3

Answer 1

1-2x <= 1/3

<=> -2x<= -2/3

<=> x>=1/3

Answer 2

\(1-2x\le\frac{1}{3}\)

\(\Leftrightarrow-2x+1\le\frac{1}{3}\Leftrightarrow-2x\le\frac{1}{3}-1\Leftrightarrow-2x\le-\frac{2}{3}\)

\(\Leftrightarrow2x\ge\frac{2}{3}\Leftrightarrow x\ge\frac{2}{3}:2=\frac{1}{3}\) (đổi chiều BĐT)

Answer 3

1 - 2 x < = 1 / 3

< = > - 2 x < = - 2 / 3

< = > x > = 1 / 3