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\(\frac{93}{42}=\frac{93:3}{42:3}=\frac{31}{14}\)
\(\frac{86}{24}=\frac{86:2}{24:2}=\frac{43}{12}\)
\(\frac{124}{80}=\frac{124:4}{80:4}=\frac{31}{20}\)
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1313/1717 = ( 1313 :101)/(1717:101)=13/17
171717/191919=(171717:10101)/(191919:10101)=17/19
231231/343343=(231231:7007)/(343343:7007)=33/49
373737/494949=(373737:10101)/(494949:10101)=37/49
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Vì rút gọn phân số \(\frac{a}{b}\)thì được phân số \(\frac{3}{4}\)
=> 4a = 3b
Nếu cộng thêm 15 đơn vị vào tử số thì được phân số bằng \(\frac{7}{6}\)
=> \(\frac{a+15}{b}=\frac{7}{6}\)
=> 6. ( a + 15 ) = 7b
=> 6a + 90 = 7b
=> 2a + 4a + 90 = 7b
Mà 3b = 4a
=> 2a + 90 + 3b = 7b
=> 2a + 90 = 4b ( 1 )
Vì 6a + 90 = 7b
=> 6a + 90 = 3b + 3b + b
Mà 3b = 4a
=> 6a + 90 = 4a + 4a + b
=> 6a + 90 = 8a + b
=> 2a + b = 90 ( 2 )
Lấy ( 1 ) trừ đi ( 2 )
=> 2a + 90 - 2a - b = 4b - 90
=> 90 - b = 4b - 90
=> 5b = 180
=> b = 36
=> a = b x 3 : 4 = 27
Vậy phân số phải tìm là \(\frac{27}{36}\)
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\(\frac{48}{96}=\frac{48:48}{96:48}=\frac{1}{2}\)
\(\frac{42}{98}=\frac{42:14}{98:14}=\frac{3}{7}\)
\(\frac{80}{240}=\frac{80:80}{240:80}=\frac{1}{3}\)
\(\frac{75}{100}=\frac{75:25}{100:25}=\frac{3}{4}\)
\(\frac{64}{720}=\frac{64:16}{720:16}=\frac{4}{45}\)
\(\frac{15}{120}=\frac{15:15}{120:15}=\frac{1}{8}\)
48/96=1/2
42/98=3/7
80/240=1/3
75/100=3/4
64/720=4/45
15/120=1/8
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1
\(\frac{2}{12;}=\frac{1}{6}\)
\(\frac{42}{63}=\frac{1}{2}\)
\(\frac{5}{60}=\frac{1}{12}\)
2.
\(\frac{3}{4}=\frac{15}{12}\) số còn lại giữ nguyên
\(\frac{20}{5}=\frac{120}{30};\frac{7}{6}=\frac{35}{30}\)
\(\frac{1}{6}\) \(\frac{7}{9}\) \(\frac{1}{12}\)
\(\frac{5}{12}và\frac{9}{12}\) \(\frac{120}{30}và\frac{35}{30}\)
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\(\frac{90}{100}=\frac{90:10}{100:10}=\frac{9}{10}\)
\(\frac{64}{128}=\frac{64:64}{128:64}=\frac{1}{2}\)
\(\frac{17}{51}=\frac{17:17}{51:17}=\frac{1}{3}\)
\(\frac{152}{608}=\frac{152:152}{608:152}=\frac{1}{4}\)
\(\frac{63}{315}=\frac{63:63}{315:63}=\frac{1}{5}\)
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ta có \(\frac{a}{b}\)
ta có a+b =108=> b= 108 - a ( ai cũng biết)
\(\frac{a}{b}\)=\(\frac{5}{7}\)ta có Tổng Quát: \(\frac{a}{b}\)=\(\frac{c}{d}\)=> a x d = b x c
=> 7 x a = 5 x b
=> 7 x a= 5 x (108 - a)
=> 7 x a= 540 - 5 x a
=> 7 x a + 5 x a =540
=> 12 x a = 540
=> a = 540 : 12=45
=> b = 108 -a= 108 -45 =63
=>\(\frac{a}{b}\)=\(\frac{45}{63}\) T I C K mk nhé
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\(\frac{11}{132}=\frac{1}{12}\)
\(\frac{63}{91}=\frac{9}{13}\)
\(\frac{270}{450}=\frac{3}{5}\)
\(\frac{51}{680}=\frac{3}{40}\)
\(\frac{225}{315}=\frac{5}{7}\)
\(\frac{234}{1404}=\frac{1}{6}\)
\(\frac{11}{132}=\frac{11:11}{132:11}=\frac{1}{12}\)
\(\frac{63}{91}=\frac{63:7}{91:7}=\frac{9}{13}\)
\(\frac{270}{450}=\frac{270:90}{450:90}=\frac{3}{5}\)
\(\frac{51}{680}=\frac{51:17}{680:17}=\frac{3}{40}\)
\(\frac{225}{315}=\frac{225:45}{315:45}=\frac{5}{7}\)
\(\frac{234}{1404}=\frac{234:234}{1404:234}=\frac{1}{6}\)
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\(\frac{3}{10}x\frac{5}{6}=4x\frac{7}{18}=\frac{14}{9}x\frac{9}{14}=1\)
kia là dấu nhân phải ko??
Nếu vậy ta có: (rút gọn từng cái rồi ráp lại cho dễ)
\(\frac{3}{10}\times\frac{5}{6}=\frac{1}{2}\times\frac{1}{2}=\frac{1}{4}\left(rutgoncheo\right)\)
\(\frac{7}{18}\times\frac{9}{14}=\frac{1}{2}\times\frac{1}{2}=\frac{1}{4}\left(rutgoncheo\right)\)
Ráp lại có: \(\frac{1}{4}\times\frac{1}{4}=\frac{1}{16}\)
42/98 = (42 : 14) / (98 : 14) = 3/7
`42/98 = (42 : 14)/(98 : 14) = 3/7`