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a. \(\dfrac{-3}{5}\)
b. \(\dfrac{-2}{3}\) c. \(\dfrac{4}{39}\) d. \(\dfrac{26}{45}\)
1,
a,-3/5
b,-1/2
c,19/39
d,1/4
e,-39/40
f,-59/56
2,
a,=
b,<
c,>
d,<
k cho mình nha
\(a,\frac{6}{-25}+\frac{-9}{25}=\frac{-3}{5}\)
\(b,\frac{1}{8}+\frac{-5}{8}=\frac{-1}{2}\)
\(c,\frac{11}{13}+\frac{-14}{39}=\frac{19}{39}\)
\(d,\frac{7}{14}+\frac{9}{-36}=\frac{1}{4}\)
a) \(\frac{1}{6}+\frac{-5}{6}\)
\(=\frac{1+\left(-5\right)}{6}\)
\(=\frac{-4}{6}=\frac{-2}{3}\)
b) \(\frac{6}{13}+\frac{-14}{39}\)
\(=\frac{18}{39}+\frac{-14}{39}\)
\(=\frac{4}{39}\)
c) \(\frac{4}{5}+\frac{4}{-18}\)
\(=\frac{4}{5}+\frac{-4}{18}\)
\(=\frac{72}{90}+\frac{-20}{90}\)
\(=\frac{52}{90}=\frac{26}{45}\)
`@` `\text {Ans}`
`\downarrow`
`1,`
`a)`
`-7/25 + (-8)/25`
`= (-7 - 8)/25`
`= -15/25`
`= -3/5`
`b)`
`6/13 + (-15)/39`
`= 18/39 + (-15)/39`
`= (18 - 15)/39`
`= 3/39`
`= 1/13`
`c)`
`5/7 + 4/(-14)`
`= 10/14 + (-4)/14`
`= (10 - 4)/14`
`= 6/14`
`= 3/7`
`d)`
`-8/18 + (-15)/27`
`= -4/9 + (-5)/9`
`= (-4-5)/9`
`= -9/9 = -1`
`2,`
`a)`
`3/5 + (-7)/4`
`= 12/20 + (-35)/20`
`= (12 - 35)/20`
`=-23/20`
`b)`
`(-2) + (-5)/8`
`= (-16)/8 + (-5)/8`
`= (-16 - 5)/8`
`= -21/8`
`c)`
`1/8 + (-5)/9`
`= 9/72 + (-40)/72`
`= (9-40)/72`
`= -31/72`
`d)`
`6/13 + (-14)/39`
`= 18/39 + (-14)/39`
`= (18 - 14)/39`
`= 4/39`
`e)`
`(-18)/24 + 15/21`
`= (-3)/4 + 5/7`
`= (-21)/28 + 20/28`
`= (-21 + 20)/28`
`= -1/28`
1. \(\frac{9}{30}=\frac{3}{10};\frac{98}{80}=\frac{49}{40};\frac{15}{1000}=\frac{3}{200}\)
Vì \(200⋮10;200⋮40\)
=> BCNN(10; 40; 200) = 200
200 : 10 = 20
200 : 40 = 5
=> \(\frac{3}{10}=\frac{3\cdot20}{10\cdot20}=\frac{60}{200}\), \(\frac{49}{40}=\frac{49\cdot5}{40\cdot5}=\frac{245}{200}\)
a . 1/25
b . -2/3
c . 4/39
d . 26/45
giải.
a)
; b) 
; c) 
; d) 
.