Hướng dẫn: Chia cả tử và mẫu cho UCLN của chúng:

ƯCLN(20, -140 ) = 20. Do đó:

\(a,\frac{22}{55}=\frac{2}{5}\)

\(b,\frac{20}{-140}=\frac{-1}{7}\) 

k mk nha thanks nhiều 

Mọi người ủng hộ mk nhé

a,22/55=2/5

b,20/-140=-1/7

a , 2/5 chia cho 11

\(\dfrac{-63}{72}=\dfrac{-7}{8}\)

\(\dfrac{20}{-140}=\dfrac{-1}{7}\)

\(\dfrac{3.10}{5.24}=\dfrac{30}{120}=\dfrac{1}{4}\)

\(\dfrac{3.7.11}{22.9}=\dfrac{231}{198}=\dfrac{7}{6}\)

\(\dfrac{8.5-8.2}{16}=\dfrac{24}{16}=\dfrac{3}{2}\)

\(\dfrac{11.4-11}{2-13}=\dfrac{33}{-11}=-3\)

102-17/ -17 = 85/-17 =-5

b: Theo đề, ta có: 

\(\dfrac{a}{74-a}=\dfrac{23}{51}\)

\(\Leftrightarrow51a=1702-23a\)

\(\Leftrightarrow74a=1702\)

hay a=23

\(\dfrac{379}{25}\)

\(14\dfrac{15}{26}=\dfrac{14x26+15}{26}=\dfrac{379}{26}\)

= (14 x 26 + 15)/26 = 379/26

\(\frac{10}{25}=\frac{10:5}{25:5}=\frac{2}{5}\)

\(\frac{5}{20}=\frac{5:5}{20:5}=\frac{1}{4}\)

\(\frac{6}{30}=\frac{6:6}{30:6}=\frac{1}{5}\)

\(\frac{60}{20}=\frac{60:20}{20:20}=3\)

B

B

B