Question

So  sánh hai p/s sau = 2 cách :

\(\frac{-14}{21}và\frac{-60}{-72}\)

Answer 1

Cách 1 :

\(\frac{-60}{-72}\)\(=\frac{60}{72}=\frac{5}{6}\)

\(\frac{-14}{21}=\frac{-2}{3}\)

Vì \(\hept{\begin{cases}6⋮3\\6⋮6\end{cases}}\Rightarrow BCNN\left(6;3\right)=6\Rightarrow MC=6\)

Có: \(\frac{-2}{3}=\frac{\left(-2\right).2}{3.2}=\frac{-4}{6}\)giữ nguyên \(\frac{5}{6}\).

Vì - 4 < 5 nên \(\frac{-4}{6}< \frac{5}{6}\)hay \(\frac{-14}{21}< \frac{-60}{-72}\)

C2 : Thấy : \(\frac{-14}{21}< 0;\frac{-60}{-72}=\frac{60}{72}>0\)

\(\Rightarrow\frac{-14}{21}< \frac{-60}{-72}\)

Answer 2

Cách 1\(\frac{-14}{21}=\frac{-14:7}{21:7}\frac{2}{3}\)

\(\frac{-60}{-72}=\frac{-60:(-12)}{-72:(-12)}=\frac{5}{6}\)

Cách 2 : Tự làm

Answer 3

So sánh mk nhầm :D

Cách 1 : \(\frac{-14}{21}=\frac{-14:7}{21:7}=\frac{-2}{3}\)

\(\frac{-60}{-72}=\frac{-60:(-12)}{-72:(-12)}=\frac{5}{6}\)

Mà \(\frac{-2}{3}< \frac{5}{6}\Rightarrow\frac{-14}{21}< \frac{-60}{-72}\)

Cách 2 : Ta thấy : \(\frac{-14}{21}< 0,\frac{-60}{-72}>0\)

=> \(\frac{-14}{21}< \frac{-60}{-72}\)