` (35 – 27) – (85-27) – 35`

` = 35 - 27 - 85 - 27 - 35`

` = (35-35) + (27 - 27) - 85`

` = 0 + 0 - 85`

` =- 85`

__________________________________

` (2002-79+15)-(-79+15)`
`=2002-79+15+79-15`
`=(-79+79)-(15-15) +2002`
`=0+0+2002`
`=2002`

_________________________________

` 65 – (-187 + 122) – 187 + 110 + 22`

` = 65 + 187 - 122 – 187 + 110 + 22`

` = (187 - 187) - (122 - 22) + 65+110`

` = 0 - 100 + 65 + 110`

` = -100 + 65 + 110`

` = -35 + 110`

` = 75`

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` - (135 - 28 + 136) + (-124 + 32 - 625)`

` =- 135 + 28 - 136 + (-124) + 32 - 625`

` = (-135 - 625) + (28 + (-124) + 32-136)`

` =  (-760) + ((-96) -104)`

` = (-760) + (-200)`

` = -960`

_____________________________________

`#BaoL i n h`

tự từ đã em, còn câu `4` nx

` (35 – 27) – (85-27) – 35`

` = 35 - 27 - 85 - 27 - 35`

` = (35-35) + (27 - 27) - 85`

` = 0 + 0 - 85`

` =- 85`

__________________________________

` (2002-79+15)-(-79+15)`
`=2002-79+15+79-15`
`=(-79+79)-(15-15) +2002`
`=0+0+2002`
`=2002`

_________________________________

` 65 – (-187 + 122) – 187 + 110 + 22`

` = 65 + 187 - 122 – 187 + 110 + 22`

` = (187 - 187) - (122 - 22) + 65+110`

` = 0 - 100 + 65 + 110`

` = -100 + 65 + 110`

` = -35 + 110`

` = 75`

_____________________________________

`#BaoL i n h`

Xét `△ABC` cân tại `A` có :

\(\widehat{A}+\widehat{B}+\widehat{C}=180^0\)

Mà : \(\widehat{A}=72^0\)

`=>` \(\widehat{B}=\widehat{C}=\dfrac{180^0-\widehat{A}}{2}\)

`=>` \(\widehat{B}=\widehat{C}=\dfrac{180^0-72^0}{2}\)

`=>`\(\widehat{B}=\widehat{C}=54^0\)

______________________________________

\(\widehat{A}=72^0\)

`=>` \(\widehat{IBC}+\widehat{ICB}=\dfrac{\widehat{ABC}}{2}+\dfrac{\widehat{ABC}}{2}=\dfrac{108^0}{2}\)

`=>` \(\widehat{IBC}+\widehat{ICB}=54^0\)

Xét `△BIC` có :

`IBC + ICB + BIC = 180^0`

`=> IBC + 54^0 = 180^0`

`=> IBC = 180^0 - 54^0`

`=> IBC = 126^0`

Vậy....

Ta có :

\(\widehat{B}=\widehat{C}\)

`BM` là tia phân giác

`=>` \(\widehat{ABM}=\widehat{MBC}=\dfrac{1}{2}\widehat{ABC}\)

`CN` là tia phân giác 

`=>` \(\widehat{ACN}=\widehat{NCB}=\dfrac{1}{2}\widehat{ACB}\)

`=>` \(\widehat{MBC}=\widehat{NCB}\)

`=> △BIC` cân tại `B`

___________________________________

`#BaoL i nh`

Lúc trả lời thì bạn cứ ghi chung `1` lần .-.

`7 - 1/2 - 3/4`

` = 28/4 - 2/4 - 3/4`

`=(28-2-3)/4`

` = 23/4`

`#BaoL i nh`

`90 = 2 . 3^2 . 5`

`180 = 2^2 . 3^2 . 5`

`315 = 3^2 . 5 .7`

`=> ƯCLN (90,180,315) = 3^2 . 5 = 45`

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`90 = { 1,2,3,5,6,9,10,15,30,45}`

`180 = { 1,2,3,4,5,6,9,10,12,15,18,20,30,36,45}`

`315 = { 1,3,5,7,9,15,21,35,45...}`

`=> ƯC ( 90,180,315) = { 1,3,5,9,15,45}`

_____________________________________________

`#BaoL i nh`

gg dịch để trưng à mn :)?

`72 = 2^3 . 3^2`

`60 = 2^2 . 3 . 5`

`=> ƯCLN(60,72) = 2^2 . 3 = 12`

________________________________________

`72 = ∈ { 1,2,3,4,6,8,9,12,18,24}`

`60 = ∈ { 1,2,3,4,5,6,10,12,15,20}`

`=> ƯCLN (722,60) = { 1,2,3,4,6,12}`

____________________________________________

`#BaoL i n h`