`1, -2/9 xx 15/17 + (-2/9) xx 2/17`

`= -2/9 xx (15/17 + 2/17)`

`= -2/9 xx 17/17`

`=-2/9xx1`

`=-2/9`

__

`-5/3 xx 6/5 + (-7/9) xx 3/10`

`= -30/15 + (-21/90)`

`= -2 + (-7/30)`

`=-60/30 +(-7/30)`

`=-67/30`

__

`15/20 xx 7/5 + (-9/7) xx (-6/4)`

`=3/4 xx7/5 + (-9/7) xx(-6/4)`

`= 21/20 + 54/28`

`= 21/20 + 27/14`

`=417/140`

__

`-25/13 xx 5/19 + (-25/13) xx 14/19`

`=-25/13 xx (5/19 +14/19)`

`=-25/13 xx 19/19`

`= -25/13 xx 1`

`=-25/13`

__

`-7/13 xx 13/5 + (-9/7) xx 5/3`

`=-7/5 +(-15/7)`

`=-124/35`

1: =-2/9(15/17+2/17)=-2/9

2: \(=\dfrac{-6}{3}+\dfrac{-21}{90}\)

=-2-7/30=-67/30

3: \(=\dfrac{3}{4}\cdot\dfrac{7}{5}+\dfrac{9}{7}\cdot\dfrac{3}{2}\)

=21/20+27/14=417/140

4: =-25/13(5/19+14/19)=-25/13

5: =-7/5-45/21=-7/5-15/7=-124/35

1: =-2/9(15/17+2/17)=-2/9

2: =34⋅75+97⋅32=34⋅75+97⋅32

=21/20+27/14=417/140

4: =-25/13(5/19+14/19)=-25/13

5: =-7/5-45/21=-7/5-15/7=-124/35

27,3 cộng 5,7 = bao nhiêu

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Đúng rồi người gì đâu mà vô đạo đức

\(=>x+7=13+25\\ =>x+7=38\\ =>x=38-7\\ =>x=31\)

\(\left(x+7\right)-25=13\\ \left(x+7\right)=13+25\\ \left(x+7\right)=35\\ x=35-7\\ x=28\)

( x + 7) -25 = 13

( x + 7)       = 13 + 25

( x + 7)       = 38

x                 = 38 - 7

x                 = 31

a: \(\left|x-7\right|+13=25\)

=>|x-7|=12

=>x-7=12 hoặc x-7=-12

=>x=19 hoặc x=-5

b: 26-|x+9|=-13

=>|x+9|=39

=>x+9=39 hoặc x+9=-39

=>x=30 hoặc x=-48

\(\dfrac{7}{16}+\dfrac{-1}{8}+\dfrac{9}{32}=\dfrac{14}{32}-\dfrac{4}{32}+\dfrac{9}{32}=\dfrac{19}{32}\)

\(\dfrac{5}{4}-\dfrac{25}{30}\times\dfrac{37}{44}+\dfrac{-25}{30}\times\dfrac{13}{44}+\dfrac{-25}{30}\times\dfrac{-6}{44}\)

\(=-\dfrac{25}{30}\times\left(\dfrac{5}{4}+\dfrac{37}{44}+\dfrac{13}{44}-\dfrac{6}{44}\right)\)

\(=-\dfrac{25}{30}\times\left(\dfrac{55}{44}+\dfrac{37}{44}+\dfrac{13}{44}-\dfrac{6}{44}\right)\)

\(=-\dfrac{25}{30}\times\dfrac{99}{44}\)

\(=-\dfrac{5}{6}\times\dfrac{9}{4}\)

\(=-\dfrac{15}{8}\)

\(\left(\dfrac{7}{16}+\dfrac{-1}{8}+\dfrac{9}{32}\right):\dfrac{5}{4}\)

\(=\left(\dfrac{14}{32}+\dfrac{-4}{32}+\dfrac{9}{32}\right):\dfrac{5}{4}\)

\(=\dfrac{19}{32}:\dfrac{5}{4}\)

\(=\dfrac{19}{32}.\dfrac{4}{5}=\dfrac{19.4}{32.5}=\dfrac{19}{40}\)

\(\dfrac{-25}{30}.\dfrac{37}{44}+\dfrac{-25}{30}.\dfrac{13}{44}+\dfrac{-25}{30}.\dfrac{-6}{44}\)

\(=\dfrac{-25}{30}.\left(\dfrac{37}{44}+\dfrac{13}{44}+\dfrac{-6}{44}\right)\)

\(=\dfrac{-25}{30}.\dfrac{44}{44}=\dfrac{-5}{6}.1=-\dfrac{5}{6}\)

a: =35/11-13/11-7/13-6/13

=2-1=1

b: =2+1/7+6/7+7/9-25/9

=2+1-2=1

c: \(=\dfrac{132}{321}\left(-\dfrac{103}{13}-\dfrac{27}{13}\right)=\dfrac{-132}{321}\cdot10=-\dfrac{440}{107}\)

Các bn ơi !Giúp mk đi!

Ai nhanh mk k nhé !

\(\left(7-x\right)-\left(25+7\right)=-25\Leftrightarrow7-x-25-7=-25\)

\(\Rightarrow\left(7-7\right)-x-25=-25\Rightarrow-x=\left(-25\right)+25=0\Rightarrow x=0 \)

\(x-\left[42+\left(-28\right)\right]=-8\Rightarrow x-\left(42-28\right)=-8\)

\(\Rightarrow x-14=-8\Leftrightarrow x=\left(-8\right)+14=6\)

\(|x-3|=|5|+|-7|\Rightarrow|x-3|=5+7=12\)

\(\Rightarrow\hept{\begin{cases}x-3=12\\x-3=-12\end{cases}}\Rightarrow\hept{\begin{cases}x=12+3=15\\x=\left(-12\right)+3=-9\end{cases}}\)

\(4-\left(7-x\right)=x-\left(13-4\right)\Rightarrow4-7+x=x-13+4\)

\(\Rightarrow\left(-3\right)+x=x-9\Leftrightarrow2x=\left(-3\right)-9=-12\Rightarrow x=-6\)