a: \(\frac{-21}{28}=\frac{-21:7}{28:7}=\frac{-3}{4}\)

\(\frac{-39}{52}=\frac{-39:\text{13}}{52:13}=\frac{-3}{4}\)

\(\frac{-24}{63}=\frac{-24:3}{63:3}=\frac{-8}{21}\)

\(\frac{12}{-21}=\frac{12:3}{-21:3}=\frac{4}{-7}\)

b: \(\frac{-270}{450}=\frac{-270:90}{450:90}=\frac{-3}{5}\)

\(\frac{11}{-143}=\frac{-11}{143}=\frac{-11:\text{11}}{143:11}=\frac{-1}{13}\)

\(\frac{-132}{156}=\frac{-132:12}{156:12}=\frac{-11}{13}\)

\(\frac{-26}{169}=\frac{-26:13}{169:13}=\frac{-2}{13}\)

\(\dfrac{-1}{13}\)

\(\dfrac{3}{5}\)

\(\dfrac{1}{6}\)

a,\(\dfrac{180}{270}=\dfrac{180:90}{270:90}=\dfrac{2}{3}\)

b,\(\dfrac{216}{225}=\dfrac{216:9}{225:9}=\dfrac{24}{25}\)

Chúc bạn học tốt!

a. 2/3

b. 72/75 (nhìn số này em mà cảm giác nó hơi sai thì chị chịu)

xin lỗi tớ mới học lớp 5 thôi

*)\(\frac{-408}{-510}=\frac{408}{510}=\frac{4\cdot102}{5\cdot102}=\frac{4}{5}\)

*)\(\frac{-270}{450}=\frac{-27}{45}=\frac{\left(-3\right)\cdot9}{5\cdot9}=\frac{-3}{5}\)

Bài 1: 

a: =-3/7

b: =-3/5

c: =1/13

d: =-1/2

Bài 2: 

a: \(=\dfrac{21\cdot11}{22\cdot9}=\dfrac{1}{2}\cdot\dfrac{7}{3}=\dfrac{7}{6}\)

b: \(=\dfrac{49\cdot8}{10}=\dfrac{196}{5}\)

a)-270/450=-3/5

b)11/-143=-1/13

c)32/12=8/3

d)-26/-156=1/6

Bạn xem mình làm đúng chưa.

a: =-1/13

b: =1/6

c: =-3/5

-1/13

1/6

-3/5

\(\frac{270}{450}=\frac{270:90}{450:90}=\frac{3}{5}\)

\(\frac{26}{156}=\frac{26:26}{156:26}=\frac{1}{6}\)

\(\frac{123123}{237237}=\frac{123123:3003}{237237:3003}=\frac{41}{79}\)

180/270=2/3

216/225=24/25

\(\frac{180}{270}=\frac{180:90}{270:90}=\frac{2}{3}\)

\(\frac{216}{225}=\frac{216:9}{225:9}=\frac{24}{25}\)

~Học tốt~