a,-200

b, -47

c,- 10 

k tui nha tui nhanh nhất đó

a) (-95) + (-105)

= -200

b) 38 + (-85)

= -47

c) 25 + (-8) + (-25) + (-2)

= 17 + -27

= -10

k mình nha

Chúc bạn học giỏi

Mình cảm ơn bạn nhiều

a ) ( - 95 ) + ( - 105 ) 

= - 200

b ) 38 + ( - 85 )

= - 47

c ) 25 + ( - 8 ) + ( - 25 ) + ( - 2 )

=[ 25 + ( - 25 ) ] + [ ( - 8 ) + ( - 2 ) ]

= 0 + ( - 10 )

= -10

k nha mình nhanh nhất !

a,x/9=5/3 = x=15

b,17/x=85/105 = x = 21

c,6/8=15/x = x =  20

d,x/8=2/3 = x = 6

 e,3/x-7=27/135 =x= 22

Ta có: \(-85-\left(x+12\right)+105=0\)

\(\Leftrightarrow20-x-12=0\)

\(\Leftrightarrow8-x=0\)

hay x=8

$-85-\left(x+12\right)+105=0$

$20-x-12=0$

$8-x=0$

 x=8

P/s: Nhớ tick cho mình. Thanks bạn

Ta có:

\(\frac{65}{85}=\frac{13}{17}\)

\(\frac{84}{105}=\frac{4}{5}\)

Vì \(\frac{13}{17}\ne\frac{4}{5}\)

=>\(\frac{65}{87}\ne\frac{84}{105}\)

1,

a,\(2020-\left(249+2020\right)+\left(249-573\right)\)

\(=2020-249-2020+249-573\)

\(=-573\)

b,\(\left|-257\right|+\left(-3\right)^0-\left(18+257\right)\)

\(=257+1-18-257\)

\(=1-18=-17\)

\(c,25.\left(85-47\right)-85.\left(47+25\right)\)

\(=25.85-25.47-47.85+85.25\)

\(=85.\left(25-47+25\right)-25.47\)

\(=85.3-25.47\)

\(=-920\)

2,

\(a,15-5.\left(x+2\right)=-30\)

\(=>5.\left(x+2\right)=15+30=45\)

\(=>x+2=\frac{45}{5}=9\)

\(=>x=7\)

\(b,\left(x+2\right)^2+5=105\)

\(=>\left(x+2\right)^2=100\)

\(=>\left(x+2\right)^2=10^2\)

\(=>x+2=10\)

\(=>x=8\)

\(c,\left|2x-5\right|-\left(-6\right)=11\)

\(=>\left|2x-5\right|=11-6=5\)

\(=>\orbr{\begin{cases}2x-5=5\\2x-5=-5\end{cases}}\)

\(=>\orbr{\begin{cases}2x=5-5=0\\2x=-5+5=0\end{cases}=>x=0}\)

\(460+85\times4=\left(x+200\right)\times4\)

\(\left(x+200\right)\times4=460+340\)

\(\left(x+200\right)\times4=800\)

\(x+200=800:4\)

\(x+200=200\)

\(x=200-200\)

\(x=0\)

~~~

\(\left(x-7\right)\left(2x-8\right)=0\)

\(+, TH1: x - 7 = 0\)

\(x=0+7\)

\(x=7\)

\(+, TH2 : 2x - 8 = 0 \)

\(2x=0+8\)

\(2x=8\)

\(x=8:2\)

\(x=4\)

~~~

\(x-280:35=5\times54\)

\(x-8=270\)

\(x=270+8\)

\(x=278\)

~~~

\(324+16\times\left(2x+3\right)=404\)

\(16\times\left(2x+3\right)=404-324\)

\(16\times\left(2x+3\right)=80\)

\(2x+3=80:16\)

\(2x+3=5\)

\(2x=5-3\)

\(2x=2\)

\(x=2:2\)

\(x=1\)

#\(Toru\)

`460 + 85 xx 4 = ( x + 200) xx 4`

`460 + 340 = (x+200)xx4`

` 800= (x+200)xx4`

`x+200=800:4`

`x+200=200`

`x=200-200`

`x=0`

__

`(x-7)(2x-8)=0`

`@ TH1`

`x-7=0`

`x=0+7`

`x=7`

`@ TH2`

`2x-8=0`

`2x=0+8`

`2x=8`

`x=8:2`

`x=4`

__

`x -280 : 35=5xx54`

`x -280 : 35=270`

`x-8=270`

`x=270+8`

`x=278`

__

`324 + 16xx(2x+3)=404`

`16xx(2x+3)=404 -324`

`16xx(2x+3)=80`

`2x+3=80:16`

`2x+3=5`

`2x=5-3`

`2x=2`

`x=2:2`

`x=1`

a) (-95)+(-105)=-200

b) 38+(-85)=-47

c) 47-107=-60

e) 25+(-8)+(-25)+(-2) 

=(-25+25) + [-8+(-2)]

=0 + (-10)

=-10

f) 18-(-2)=18+2=20

g) -16-5--21

=-16-5+21

=-21+21

=0

h) -11+23-(-21)

=-11+23+21

=12+21

=33

i) -13-15+5

=-18+5

=-13

 Học Tốt 

i) -13-15+5

=-28+5

=-23

Câu i mình làm nhầm ở trên thông cảm