\(12-(23-17)+\left|-15\right|=13-x-(23-8+\left|-9\right|)\)

\(\Rightarrow12-6+15=13-x-(23-8+9)\)

\(\Rightarrow12-6+15=13-x-24\)

\(\Rightarrow21=13-x-24\)

\(\Rightarrow x=13-24-21\)

\(\Rightarrow x=-32\)

\(\text{Vậy : }x=-32\)

12-( 23 - 17 )+ 15 = 13 -x - (23 - 8 + 9 )

12-23+17+15=13-x-23+8-9

12+17+15-23=13+8-9-x

29+15-23= 21-9 -x

44-23=12-x

21=12-x

12-x=21

x=12-21

x= -9

12 - ( 23 - 17 ) + \(|-15|=13-x-\left(23-8+|-9|\right)\)

= 12 - 6            + 15            = 13 - x - ( 23 - 8 + 9 )

= 12 - 6 + 15 = 13 - x - 24

= 21 = 13 - x - 24

=> x = 13 - 24 - 21

=> x = -32

Vậy x = -32

\(x-\left(\frac{20}{11.13}+\frac{20}{13.15}+\frac{20}{15.17}+...+\frac{20}{53.55}\right)=\frac{3}{11}.\)

\(x-\frac{20}{2}.\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}+\frac{1}{15}-\frac{1}{17}+...+\frac{1}{53}-\frac{1}{55}\right)=\frac{3}{11}\)

\(x-10.\left(\frac{1}{11}-\frac{1}{55}\right)=\frac{3}{11}\)

\(x-10\cdot\frac{4}{55}=\frac{3}{11}\)

\(x-\frac{8}{11}=\frac{3}{11}\)

 x = 1

A=[(1+9)+(3+7)+(5+15)+(11+13)].2

A=[10+10+20+24].2

A=64.2

A=128

B=(17+23)+(19+21)+(23+27)+(25+29)

B=40+40+50+54

B=tự tính

A=(1+9)+(3+7)+(5+15)+(7+13)+(11.2)

A=10+10+10+10+22

A=40+22

A=62

mình làm câu A thôi nhé

14 x 23 - 4 x 23 - 4(x + 5) = 30

(14 - 4) x 23 - 4(x + 5) = 30

      10  x 23 - 4(x + 5) = 30

           230 - 4(x + 5) = 30

                    4(x + 5) = 230 - 30

                    4(x + 5) = 200

                        x + 5 = 200 : 4

                        x + 5 = 50

                              x = 50 - 5

                               x = 45

a)

13 x 81 + 13 x 19 

= 13 x ( 81 + 19 )

= 13 x 100 = 1300

b)

246 x 83 + 246 x 17

= 246 x ( 83 + 17 )

= 246 x 100

= 24600

c)

246 x 83 + 247 x 17 

= 246 x 83 + 246 x 17 + 17

= 246 x ( 83 + 17 ) + 17

= 246 x 100 + 17 

= 24600 + 17

= 24617

          Ủng hộ mik nhak !!!

   13x81+13x19

=13x(19+81)

=13x100

=1300

  246x83+246x17

=246x(83+17)

=246x100

=24600

(81+19) x13=

100x13

=1300

cac cau con lai cung vay do

`a,`

\((- 5) .x + 17 = - 23\)

`\Rightarrow (-5)x = -23 - 17`

`\Rightarrow (-5)x =-40`

`\Rightarrow x = (-40) \div (-5)`

`\Rightarrow x = 8`

Vậy,` x = 8`

`b,`

\(8 + 4x = - 24\)

`\Rightarrow 4x = -24 - 8`

`\Rightarrow 4x = -32`

`\Rightarrow x = -32 \div 4`

`\Rightarrow x = -8`

Vậy, `x = -8`

`c,`

\(32 – 12 + x = -10\)

`\Rightarrow 20 + x = -10`

`\Rightarrow x = -10 - 20`

`\Rightarrow x = -30`

Vậy, `x = -30`

`d,`

\(x – 87 + 13 = - 100\)

`\Rightarrow x - 87 = -100 - 13`

`\Rightarrow x - 87 = -113`

`\Rightarrow x = -113 + 87`

`\Rightarrow x = -26`

Vậy, `x = -26.`

cậu dùng máy tính ý vừa nhanh vừa tiện :))

Kết quả = - 790

Khá dễ

k nha!!!