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

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

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

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

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

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

a. \(\dfrac{8,5-8,2}{16}=\dfrac{0,3}{16}=\dfrac{3}{160}\)

b. \(\dfrac{2\cdot14}{7\cdot8}=\dfrac{1\cdot2}{1\cdot4}=\dfrac{2}{4}=\dfrac{1}{2}\)

c. \(\dfrac{11\cdot4-11}{2-13}=\dfrac{11\left(4-1\right)}{-11}=\dfrac{1\cdot3}{-1}=-3\)

d. \(\dfrac{49+7\cdot49}{49}=\dfrac{49\cdot\left(1+7\right)}{49}=\dfrac{8}{1}=8\)

a) \(\dfrac{8,5-8,2}{16}=\dfrac{0,3}{16}=\dfrac{0,3\cdot10}{16\cdot10}=\dfrac{3}{160}\)

b) \(\dfrac{17\cdot5-17}{3-20}=\dfrac{17\cdot\left(5-1\right)}{-17}=\dfrac{1\cdot4}{-1}=-4\)

a)

\(\dfrac{8\cdot5-8\cdot2}{16}=\dfrac{8\left(5-2\right)}{16}=\dfrac{3}{2}\)

b)

\(\dfrac{17\cdot5-17}{3-20}=\dfrac{17\left(5-1\right)}{-17}=\dfrac{4}{-1}=-4\)

a) $\frac{4.7}{9.32}=\frac{4.7}{\mathrm{9.4.8}}=\frac{7}{9.8}=\frac{7}{72}$

b) $\frac{3.21}{14.15}=\frac{\mathrm{3.3.7}}{\mathrm{2.7.3.5}}=\frac{3}{2.5}=\frac{3}{10}$

c) $\frac{\mathrm{2.5.13}}{26.35}=\frac{\mathrm{2.5.13}}{\mathrm{2.13.5.7}}=\frac{1}{7}$

d) $\frac{9.6–9.3}{18}=\frac{9.(6–3)}{9.2}=\frac{6–3}{2}=\frac{3}{2}$

e) $\frac{17.5–17}{3–20}=\frac{17.(5–1)}{–17}=\frac{5–1}{–1}=–4$

f) $\frac{49+7.49}{49}=\frac{49.(1+7)}{49}=1+7=8$

a) \(\dfrac{4.7}{9.32}=\dfrac{4.7}{9.4.8}=\dfrac{7}{72}\)

b) \(\dfrac{3.21}{14.15}=\dfrac{3.3.7}{2.7.3.5}=\dfrac{3}{10}\)

c) \(\dfrac{2.5.13}{26.35}=\dfrac{2.5.13}{2.13.5.7}=\dfrac{1}{7}\)

d) \(\dfrac{9.6-9.3}{18}=\dfrac{9\left(6-3\right)}{9.2}=\dfrac{3}{2}\)

e) \(\dfrac{17.5-17}{3-20}=\dfrac{17\left(5-1\right)}{-17}=\dfrac{5-1}{-1}=-4\)

f) \(\dfrac{49+7.49}{49}=\dfrac{49\left(1+7\right)}{49}=8\)

\(\frac{4\cdot7}{9\cdot32}=\frac{4\cdot7}{9\cdot8\cdot4}=\frac{7}{8\cdot9}=\frac{7}{72}\)

\(\frac{2\cdot5\cdot13}{26\cdot35}=\frac{2\cdot5\cdot13}{2\cdot13\cdot7\cdot5}=\frac{1}{7}\)

\(\frac{3\cdot21}{14\cdot15}=\frac{3\cdot3\cdot7}{2\cdot7\cdot3\cdot5}=\frac{3}{2\cdot5}=\frac{3}{10}\)

\(\frac{9\cdot6-9\cdot3}{18}=\frac{9\cdot\left(6-3\right)}{9\cdot2}=\frac{9\cdot3}{9\cdot2}=\frac{3}{2}\)

\(\frac{17\cdot5-17}{3-20}=\frac{17\cdot\left(5-1\right)}{-17}=\frac{17\cdot4}{17\cdot\left(-1\right)}=\frac{4}{-1}=-4\)

\(45dm^2=0,45m^2\)

\(300cm^2=0,03m^2\)

\(57500mm^2=0,0575m^2\)

a) .

b)

c)

d)

e)

.

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

*Rút gọn :

`(8.5-8.2)/16=(8.(5-2))/(8.2)=(8.3)/(8.2)=3/2`

`(11.4-11)/(2-13)=(11.(4-1))/(-11)=(11.3)/(-1.11)=3/(-1)=-3`

*Quy đồng :

- Ta có : `-3=(-3)/1`

UCLN(2,1)=2

$\to\begin{cases} \dfrac32=\dfrac32\\\dfrac{-3}1=\dfrac{-6}2\end{cases}$