Question

Tìm x:

\(\frac{2}{5}< \frac{1}{x}< \frac{3}{5}\)

Answer 1

ta gọi 1/x là Y

2/5=4/10

3/5=6/10

=>4/10<Y<6/10=>Y=5/10=1/2

=>X=2

Answer 2

Ta có \(\frac{2}{5}< \frac{1}{x}< \frac{3}{5}\)

\(\Rightarrow\frac{2.3}{5.3}< \frac{1.6}{6.x}< \frac{3.2}{5.2}\)

\(\Rightarrow\frac{6}{15}< \frac{6}{6x}< \frac{6}{10}\)

\(\Rightarrow15>6x>10\)

\(\Rightarrow6x=12\Rightarrow x=2\)

Answer 3

x bằng 2

Answer 4

Ta có: \(\frac{2}{5}< \frac{1}{x}< \frac{3}{5}\Leftrightarrow\frac{4}{10}< \frac{1}{x}< \)\(\frac{6}{10}\)

Mà: \(\frac{4}{10}< \frac{5}{10}< \frac{6}{10}\)

\(\Rightarrow\frac{1}{x}=\frac{5}{10}\)\(\Rightarrow\frac{5}{5\times x}=\frac{5}{10}\Rightarrow5\times x=10\)

                                                                           \(x=10:5\)

                                                                           \(x=2\)

                                        Đáp số: x=2

                                                          

Answer 5

\(\frac{2}{5}< \frac{1}{x}< \frac{3}{5}\Rightarrow\frac{4}{10}< \frac{1}{x}< \frac{6}{10}\)

\(\Rightarrow\frac{1}{x}=\frac{5}{10}=\frac{1}{2}\Rightarrow x=2\)

Answer 6

\(\frac{2}{5}< \frac{1}{x}< \frac{3}{5}\Rightarrow\frac{2.3}{5.3}< \frac{1.6}{x.6}< \frac{3.2}{5.2}\Rightarrow\frac{6}{15}< \frac{6}{x.6}< \frac{6}{10}\Rightarrow15>x.6>10\Rightarrow x=6\Rightarrow\)

Answer 7

sory x=2 viết nhầm