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`@` `\text {Ans}`
`\downarrow`
`1/3+6/9+4/5+5/25`
`= 1/3+2/3+4/5+1/5`
`= 1+1`
`= 2`
`4/7*2/5+4/7*3/5-1/7`
`= 4/7*(2/5+3/5)-1/7`
`= 4/7*1-1/7`
`= 4/7-1/7=3/7`
.....................................................
a) \(3\frac{1}{2}+4\frac{5}{7}-5\frac{5}{14}\)
\(=3\frac{7}{14}+4\frac{10}{14}-5\frac{5}{14}\)
\(=\left(3+4-5\right)+\left(\frac{7}{14}+\frac{10}{14}-\frac{5}{14}\right)\)
\(=2+\frac{6}{7}=2\frac{6}{7}=\frac{20}{7}\)
b) \(\frac{1}{2}+\left(\frac{1}{2}:5\right)\frac{1}{2}\)
\(=\frac{1}{2}+\left(\frac{1}{10}\right)\frac{1}{2}\)
\(=\frac{1}{2}+\frac{6}{5}=\frac{11}{10}\)
`3/4 + 5/6 = 9/12 + 10/12 = 19/12`
`1/2 + 7/12 = 6/12 + 7/12 = 13/12`
`2/3 xx 3/4 = 2/4 = 1/2`
`7/4 : 2 = 7/4 xx 1/2 = 7/8`
\(a,\dfrac{3}{4}+\dfrac{5}{6}=\dfrac{18}{24}+\dfrac{20}{24}=\dfrac{38}{24}=\dfrac{19}{12}\)
\(b,\dfrac{1}{2}+\dfrac{7}{12}=\dfrac{6}{12}+\dfrac{7}{12}=\dfrac{13}{12}\)
\(c,\dfrac{2}{3}x\dfrac{3}{4}=\dfrac{2}{4}\)
\(d,\dfrac{7}{4}:2=\dfrac{7}{4}x\dfrac{1}{2}=\dfrac{7}{8}\)
\(\left(6:3,5-1\dfrac{1}{6}\times\dfrac{6}{7}\right):\left(4,2\times\dfrac{10}{11}+5\dfrac{2}{11}\right)\\ =\left(\dfrac{12}{7}-\dfrac{7}{6}\times\dfrac{6}{7}\right):\left(\dfrac{21}{5}\times\dfrac{10}{11}+\dfrac{57}{11}\right)\\ =\left(\dfrac{17}{7}-1\right):\left(\dfrac{42}{11}+\dfrac{57}{11}\right)\\ =\dfrac{10}{7}:9\\ =\dfrac{10}{63}\)
\(\left(6:\dfrac{3}{5}-1\dfrac{1}{6}\times\dfrac{6}{7}\right):\left(4,2\times\dfrac{10}{11}+5\dfrac{2}{11}\right)\)
\(=\left(6\times\dfrac{5}{3}-\dfrac{7}{6}\times\dfrac{6}{7}\right):\left(\dfrac{21}{5}\times\dfrac{10}{11}+\dfrac{57}{11}\right)\)
\(=\left(10-1\right):\left(\dfrac{42}{11}+\dfrac{57}{11}\right)=9:9=1\)
5 và 1/7 : x = 4
= 36/7 : x = 4
= x = 36/7:4
= x = 9/7
`5 1/7 : x =4`
`(5xx7+1)/7 : x = 4`
`36/7 : x = 4`
`x=36/7:4`
`x=36/7xx1/4`
`x=9/7`