\(\dfrac{-15}{5,1}=\dfrac{-35}{11,9}\\ \Rightarrow\dfrac{-15}{-35}=\dfrac{5,1}{11,9};\dfrac{11,9}{5,1}=\dfrac{-35}{-15};\dfrac{5,1}{-15}=\dfrac{-35}{11,9}\)

1/ \(\frac{5}{-9}=\frac{15}{-27}\)

2/ \(\frac{-27}{-9}=\frac{15}{5}\)

3/ \(\frac{5}{15}=\frac{-9}{-27}\)

4/ \(\frac{-9}{5}=\frac{-27}{15}\)

tíc mình nha

5/(-9)=15/(-27)

5/15=-9/(-27)

-27/(-9)=15/5

-27/15=(-9)/5

\(\dfrac{-15}{-35}=\dfrac{5.1}{11.9};\dfrac{-35}{-15}=\dfrac{11.9}{5.1};\dfrac{5.1}{-15}=\dfrac{11.9}{-35}\)

a, vì  1.16 = 2.8

Vậy ta có các tỉ lệ thức: \(\dfrac{1}{2}\) = \(\dfrac{8}{16}\); \(\dfrac{1}{8}\) = \(\dfrac{2}{16}\); \(\dfrac{2}{1}\) = \(\dfrac{16}{8}\); \(\dfrac{16}{2}\) = \(\dfrac{8}{1}\)

b, \(\dfrac{3}{2}\) : \(\dfrac{2}{3}\) = \(\dfrac{1}{4}\) : \(\dfrac{1}{9}\) ⇒ \(\dfrac{3}{2}\).\(\dfrac{1}{9}\) = \(\dfrac{1}{4}\).\(\dfrac{2}{3}\)

     \(\dfrac{3}{2}\) : \(\dfrac{1}{4}\) = \(\dfrac{2}{3}\)  : \(\dfrac{1}{9}\)

      \(\dfrac{1}{9}\) :  \(\dfrac{1}{4}\) = \(\dfrac{2}{3}\) : \(\dfrac{3}{2}\)

      \(\dfrac{1}{9}\) : \(\dfrac{2}{3}\) = \(\dfrac{1}{4}\) : \(\dfrac{3}{2}\) 

Các tỉ lệ thức lập được là :

\(-\frac{15}{5,1}=-\frac{35}{11,9}\)

\(\frac{15}{35}=\frac{5,1}{11,9}\)

\(\frac{11,9}{5,1}=\frac{35}{15}\)

\(\frac{11,9}{-35}=-\frac{15}{5,1}\)

~Study well~

Nếu sai thi thông cảm cho mk nhé.

#)Giải :

Ta có : \(-\frac{15}{5,1}=-\frac{35}{11,9}\Rightarrow-\frac{5,1}{15}=-\frac{11,9}{35}\)

\(\Rightarrow-\frac{11,9}{35}=-\frac{5,1}{15}\)

\(\Rightarrow-\frac{11,9}{35}=-\frac{15}{5,1}\)