a: \(\frac{60}{72}=\frac{60:12}{72:12}=\frac56\)

\(\frac{24}{36}=\frac{24:12}{36:12}=\frac23=\frac{2\times2}{3\times2}=\frac46\)

mà 5>4

nên \(\frac{60}{72}>\frac{24}{36}\)

b: \(\frac{-13}{18}=\frac{-13\times2}{18\times2}=\frac{-26}{36}\)

\(\frac{-7}{12}=\frac{-7\times3}{12\times3}=\frac{-21}{36}\)

mà -26<-21

nên \(-\frac{13}{18}<-\frac{7}{12}\)

c: \(\frac{4}{15}=\frac{4\times6}{15\times6}=\frac{24}{90}\)

\(\frac{7}{18}=\frac{7\times5}{18\times5}=\frac{35}{90}\)

mà 24<35

nên \(\frac{4}{15}<\frac{7}{18}\)

d: \(\frac{123}{321}>0;0>-\frac{312}{213}\)

Do đó: \(\frac{123}{321}>-\frac{312}{213}\)

   \(\dfrac{3}{17}\) .\(\dfrac{6}{29}\) - \(\dfrac{3}{17}\).\(\dfrac{35}{29}\) + 2022\(\dfrac{3}{17}\)

= (\(\dfrac{3}{17}\).\(\dfrac{6}{29}\) - \(\dfrac{3}{17}\).\(\dfrac{35}{29}\)) + 2022 + \(\dfrac{3}{17}\)

= \(\dfrac{3}{17}\).(\(\dfrac{6}{29}\) - \(\dfrac{35}{29}\)) + 2022 + \(\dfrac{3}{17}\)

= \(\dfrac{3}{17}\).(-1) + 2022 + \(\dfrac{3}{17}\)

 = (- \(\dfrac{3}{17}\) + \(\dfrac{3}{17}\)) + 2022

= 0 + 2022

= 2022 

b; \(\dfrac{5}{6}\) - (\(\dfrac{1}{3}\) + \(\dfrac{1}{2}\)).20%

= \(\dfrac{5}{6}\) - \(\dfrac{5}{6}\).\(\dfrac{1}{5}\)

= \(\dfrac{5}{6}-\dfrac{1}{6}\)

= \(\dfrac{4}{6}\) 

= \(\dfrac{2}{3}\)

Bài 1:

\(\dfrac{-5}{18}=\dfrac{-20}{72};\dfrac{7}{-24}=\dfrac{-21}{72}.\)

\(\dfrac{-15}{-40}=\dfrac{3}{8}=\dfrac{9}{24};\dfrac{24}{-72}=\dfrac{-1}{3}=\dfrac{-8}{24}.\)

Bài 3:

a) \(\dfrac{2}{3}h=\dfrac{8}{12}h;\dfrac{3}{4}h=\dfrac{9}{12}h.\Rightarrow\dfrac{2}{3}h< \dfrac{3}{4}h.\)

b) \(\dfrac{4}{5}km/h=\dfrac{8}{10}km/h;\dfrac{9}{10}km/h.\Rightarrow\dfrac{4}{5}km/h< \dfrac{9}{10}km/h.\)

5/7>6/21

18/24>15/25

12/13=1212/1313

\(\dfrac{5}{7}\)>\(\dfrac{6}{21}\)

\(\dfrac{18}{24}\)>\(\dfrac{15}{25}\)

\(\dfrac{12}{13}\)=\(\dfrac{1212}{1313}\)

a. 18/72 = 1/4

    15/20 = 3/4

vì 1/4<3/4 nên 18/72<15/20

b. 24/36 = 2/3

    20/50 = 2/5

2/3>2/5 nên 24/36>20/50

a, \(\dfrac{18}{72}\) = \(\dfrac{18:18}{72:18}\) = \(\dfrac{1}{4}\);     \(\dfrac{15}{20}\) = \(\dfrac{3}{4}\)

     Vì \(\dfrac{1}{4}\) < \(\dfrac{3}{4}\)  nên \(\dfrac{18}{72}\) < \(\dfrac{15}{20}\)

b, \(\dfrac{24}{36}\) = \(\dfrac{24:12}{36:12}\) = \(\dfrac{2}{3}\);          \(\dfrac{20}{50}\) = \(\dfrac{20:10}{50:10}\) = \(\dfrac{2}{5}\)

Vì \(\dfrac{2}{3}\) > \(\dfrac{2}{5}\) nên \(\dfrac{24}{36}\) > \(\dfrac{20}{50}\) 

12/18=2/3=36/54

Câu 1:

a; x/7 = - 9/14

x = - 9/14 x 7

x = - 9/2

Vậy x = -9/2

b; - 16/36 = - y/4

-4/9 = - y/4

y = -4/9 x (-4)

y = 16/9

Vậy y = 16/9

Câu 1c:

-5/12 = x/60

x = -5/12 x 60

x = - 25

Vậy x = - 25

d: -4/8 = x/-10 = -7/y

-4/8 = x/-10

x = -4/8 x (-10)

x = 5

-4/8 = -7/y

y = - 7 : (-4/8)

y = 7 x 8/4

y = 14

Vậy (x; y) = (5; 14)