Bài 1: 

a: 3/-5=-3/5=-6/10

b: 5/-10=-1/2=-5/10

c: -4/-9=4/9=8/18

d: -6/8=-3/4=-9/12

e: 0/-10=0

f: 0/-6=0

a ) 3 − 5 = 6 10 = − 9 15 b ) 5 10 = − 1 2 = − 2 4

c ) − 4 − 9 = 8 18 = 12 27 d ) − 6 − 8 = 3 4 = 9 12

e ) 0 − 10 = 0 2 = 0 3 f ) 0 − 6 = 0 2 = 0 3

a)  2 − 5 = − 3 5 = − 6 10 ;

b)  5 − 10 = − 5 10 = − 10 20 ;

c)  − 6 − 8 = 6 8 = 12 16 ;

d)  0 − 10 = 0 10 = 0 20

-3/5; 13/7; -1/2; -2/1

a) 1 và $\frac{2}{5}$

$1 = \frac{1}{1} = \frac{{1 \times 5}}{{1 \times 5}} = \frac{5}{5}$

Ta có $\frac{5}{5}$ và $\frac{2}{5}$

b) 2 và $\frac{3}{8}$

$2 = \frac{2}{1} = \frac{{2 \times 8}}{{1 \times 8}} = \frac{{16}}{8}$

Ta có $\frac{{16}}{8}$ và $\frac{3}{8}$

c) $\frac{1}{3}$ và 5

$5 = \frac{5}{1} = \frac{{5 \times 3}}{{1 \times 3}} = \frac{{15}}{3}$

Ta có $\frac{1}{3}$ và $\frac{{15}}{3}$

a: \(1=\dfrac{1}{1}=\dfrac{1\cdot5}{5\cdot5}=\dfrac{5}{5}\)

\(\dfrac{2}{5}=\dfrac{2}{5}\)

b: \(2=\dfrac{2\cdot8}{1\cdot8}=\dfrac{16}{8}\); \(\dfrac{3}{8}=\dfrac{3}{8}\)

c: \(5=\dfrac{5}{1}=\dfrac{5\cdot3}{1\cdot3}=\dfrac{15}{3};\dfrac{1}{3}=\dfrac{1}{3}\)

a ) 1 − 8 = − 2 16 = − 3 24 b ) 3 − 6 = − 1 2 = − 2 4

c ) − 7 − 8 = 14 16 = 21 24 d ) − 12 − 15 = 4 5 = 8 10

e ) 0 − 11 = 0 2 = 0 3 f ) 0 − 103 = 0 2 = 0 3

Giải

\(\frac{3}{-4}=\frac{-3}{4};\frac{-5}{-7}=\frac{5}{7};\frac{2}{-9}=\frac{-2}{9};\frac{-11}{-10}=\frac{11}{10}\)

Okay !

\(\frac{3}{-4}=\frac{-3}{4}\)

\(\frac{-5}{-7}=\frac{5}{7}\)

\(\frac{2}{-9}=\frac{-2}{9}\)

\(\frac{-11}{-10}=\frac{11}{10}\)

\(\frac{3}{-4}=\frac{-3}{4}\)

\(\frac{-5}{-7}=\frac{5}{7}\)

\(\frac{2}{-9}=\frac{-9}{2}\)

\(\frac{-11}{-10}=\frac{11}{10}\)

 Ta có: \(\frac{1}{{ - 2}} = \frac{{1.( - 1)}}{{ - 2.( - 1)}} = \frac{{ - 1}}{2}\)

\(\frac{{ - 3}}{{ - 5}} = \frac{{ - 3.( - 1)}}{{ - 5.( - 1)}} = \frac{3}{5}\)

\(\frac{2}{{ - 7}} = \frac{{2.( - 1)}}{{ - 7.( - 1)}} = \frac{{ - 2}}{7}\).

\(\dfrac{1}{-2}=\dfrac{-1}{2}\)

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

\(\dfrac{2}{-7}=\dfrac{-2}{7}\)