1.cùng màu a.1\6+-5\6 b.7\-25+-8\25 c.6\13+-15\39 d.5\7+4\-14 e.-8\18+-15\27 giúp em em vote 5 sao ạ uy tín!

Lời giải: 

`1`

`a. 1/6 + (-5)/6`

`= (1+ -5)/6`

`= (-4)/6 = (-2)/3`

`b. 7/-25 + -8/25`

`= (-7)/25 + (-8)/25`

`= (-7+ -8)/25`

`= (-15)/25 = (-3)/5`

`c. 6/13+(-15)/39`

`=18/39+(-15)/39`

`= 3/39 = 1/13`

`d. 5/7+4/-14`

`= 10/14+(-4)/14`

`= 3/7`

`e. (-8)/18+(-15)/27`

`= (-4)/9 - 5/9`

`= (-9)/9 = -1`

`@Don``na`

a) $\dfrac{1}{6}$ + $\dfrac{-5}{6}$ = $\dfrac{-4}{6}$ = $\dfrac{-2}{3}$

b) $\dfrac{7}{-25}$ + $\dfrac{-8}{25}$ = $\dfrac{-7}{25}$ + $\dfrac{-8}{25}$

= $\dfrac{-15}{-25}$ = $\dfrac{-3}{5}$

c, $\dfrac{6}{13}$ + $\dfrac{-15}{39}$ = $\dfrac{18}{30}$ + $\dfrac{-15}{39}$

= $\dfrac{3}{39}$ = $\dfrac{1}{13}$

d, $\dfrac{5}{7}$ + $\dfrac{4}{-14}$ = $\dfrac{10}{14}$ + $\dfrac{-4}{14}$

= $\dfrac{6}{14}$ = $\dfrac{3}{7}$

e, $\dfrac{-8}{18}$ + $\dfrac{-15}{27}$ = $\dfrac{-4}{9}$ + $\dfrac{-5}{9}$

= $\dfrac{-9}{9}$ = -1