thực hiện phép tính a.1\6 - -5\6 b.6\13 - -14\39 c.4\5 - 4\-18 d.7\21 - 9\-36 e.-12\18 - -21\35 f.-3\21 - 6\42 giúp em em vote 5 sao ạ uy tín!

Đáp án + Giải thích các bước giải:

`1/6 - (-5)/6 = 1/6 + 5/6 = (1 + 5)/6 = 6/6 = 1`

`6/13 - (-14)/39 = 6/13 + 14/39 = 18/39 + 14/39 = 32/39`

`4/5 - 4/(-18) = 4/5 - (-2)/9 = 4/5 + 2/9 = 36/45 + 10/45 = 46/45`

`7/21 - 9/(-36) = 7/21 + 9/36 = 1/3 + 1/4 = 4/12 + 3/12 = 7/12`

`-12/18 - (-21)/35 = -12/18 + 21/35 = -2/3 + 3/5 = -10/15 + 9/15 = -1/15`

`-3/21 - 6/42 = -1/7 - 1/7 = -2/7` 

`@`𝔗𝔖𝔄

Lời giải `:`

$a)$ $\frac{1}{6}- \frac{-5}{6} = \frac{1}{6}+\frac{5}{6} = \frac{\left(1+5\right)}{6} = 1$

$b)$ $\frac{6}{13}-\frac{(-14)}{39}\\=\frac{\left(6\cdot3\right)}{\left(13\cdot3\right)}+\frac{14}{39}\\=\frac{18}{39}+\frac{14}{39}\\=\frac{32}{39}$

$c)$ $\frac{4}{5}-\frac{4}{(-18)}\\=\frac{\left(4\cdot18\right)}{\left(5\cdot18\right)}+\frac{\left(-4\cdot-5\right)}{\left(-18\cdot-5\right)}\\=\frac{72}{90}+\frac{20}{90}\\=\frac{46}{45}$

$d)$ $\frac{7}{21}-\frac{9}{(-36)}\\=\frac{\left(7\cdot12\right)}{\left(21\cdot12\right)}+\frac{\left(-9\cdot-7\right)}{\left(-36\cdot-7\right)}\\=\frac{\left(84+63\right)}{252}\\=\frac{7}{12}$

`e)` `-12/18 - (-21)/35 `

`= -12/18 + 21/35 `

`= -2/3 + 3/5 `

`= -10/15 + 9/15`

`= -1/15`

`f)` `-3/21 - 6/42 = -1/7 - 1/7 = -2/7`