c) 84:(324:18+36-x)+15=19

=> 84:(324:18+36-x)=19-15

=> 84:(324:18+36-x)=4

=> 324:18+36-x=84:4=21

=> 18+36-x  = 21

=> 54-x = 21

=> x = 54-21

=> x = 33

 84 : ( 18+36-x) +15= 19
 84:(54-x)+15=19

 84:(54-x) =19+15

84:(54-x)= 34

54-x =84:34 

54-x =\(\frac{42}{17}\)

x = 54 - \(\frac{42}{17}\)

x= \(\frac{816}{17}\)

a  \(\dfrac{5}{12}\times\dfrac{4}{9}\) + \(\dfrac{4}{9}\times\dfrac{7}{12}\)

= \(\dfrac{4}{9}\times\left(\dfrac{5}{12}+\dfrac{7}{12}\right)\)

= \(\dfrac{4}{9}\times\dfrac{12}{12}\)

= \(\dfrac{4}{9}\)

b(\(\dfrac{13}{21}\times\dfrac{7}{8}-\dfrac{12}{21}\times\dfrac{7}{8}\)) x 12 

(\(\dfrac{7}{8}\times\left(\dfrac{13}{21}-\dfrac{12}{21}\right)\))x 12

\(\dfrac{7}{8}\times\dfrac{1}{21}\) x 12

\(\dfrac{139}{14}\)

\(\dfrac{7}{11}+\dfrac{3}{4}+\dfrac{4}{11}+\dfrac{8}{17}+\dfrac{1}{4}+\dfrac{18}{34}\)

=\(\left(\dfrac{7}{11}+\dfrac{4}{11}\right)+\left(\dfrac{3}{4}+\dfrac{1}{4}\right)\) + \(\dfrac{18}{34}\) 

=1 + 1 + \(\dfrac{18}{34}\)

=\(\dfrac{34}{17}\)

2)a 3,71 + (632 - x) = 415 

                  632 - x= 415 - 3,71 

                  632 -x = 411,59

                          x = 632 - 411,59 

                          x = 220,41

b, 140 : (5x \(x\) - 15) = 4 

              5x \(x\) - 15 = 140 : 4

             5x \(x\) - 15 = 35 

              5x \(x\) = 35 + 15 

             5x \(x\) = 50 

                  \(x\) = 50 : 5 

                 \(x\) = 10

36 x 950 + 18 x 726 x 2 + 3 x 324 x 12

= 36 x 950 + 36 x 726 +36 . 324

=36(950 + 726 + 324 )

= 36 . 2000

= 72000

hâm rồi à gia linh

 36-4x9 = 36 - 36 = 0 Vì số nào nhân với 0 thì cũng bằng 0 nên phép tính đó bằng 0

a) 42 - x = 5

x = 42 - 5

x = 37

b) 15.(x + 4) = 75

x + 4 = 75 : 15

x + 4 = 5

x = 5 - 4

x = 1

d) x + 18 = 12

x = 12 - 18

x = -6

e) 2x - 15 = -19

2x = (-19) + 15

2x = -4

x = -4 : 2

x = -2

f) 36 : (x^3 - 12) = -3

x^3 - 12 = 36 : (-3)

x^3 - 12 = -12

x^3 = 0

=> x = 0

g)x + 15 = 35

x = 35 - 15

x = 20

h) 2x - 13 = 3^2

2x - 13 = 9

2x = 9 + 13

2x = 22

x = 22 : 2

x = 11

a) 42-x=5

         x=42-5

         x= 37

b)15*(x+4)=75

        x+4=75:15

        x+4=5

        x    =5-4

       x     = 1

a) 42 - x = 5

x = 42 - 5

x = 37

b) 15.(x + 4) = 75

x + 4 = 75 : 15

x + 4 = 5

x = 5 - 4

x = 1

d) x + 18 = 12

x = 12 - 18

x = -6

e) 2x - 15 = -19

2x = (-19) + 15

2x = -4

x = -4 : 2

x = -2

f) 36 : (x^3 - 12) = -3

x^3 - 12 = 36 : (-3)

x^3 - 12 = -12

x^3 = 0

=> x = 0

g)x + 15 = 35

x = 35 - 15

x = 20

h) 2x - 13 = 3^2

2x - 13 = 9

2x = 9 + 13

2x = 22

x = 22 : 2

x = 11

11+12+13+14+15+16+17+18+19+...+89+88+87+86+85+84+83+82

=( 11 + 89 )+(12+88)+(13+87)+(14+86)+(15+85)+(16+84)+(17+83)+(18+82)+19

=100+100+100+100+100+100+100+100+19

=800+19

=819

1. -86 + ( -14)

= -86 - 14

= -100

2. 123 + ( -36)

= 123 - 36

= 87

3. ( -44) - ( -66)

= -44 + 66

= 22

4. -82 + (-28)

= -82 - 28

= -110

5. 83 + ( -17)

= 83 - 17

= 66

Các bài khác làm tương tự nha bạn

1/ (-86)+(-14)=-86-14=-100

2/123+(-36)=123-36=87

3/(-44)-(-66)=-44+66=22

4/-82+(-28)=-82-28=-110

5/83+(-17)=83-17=66

6/(-83)-33=(-83)+(-33)=-116

7/ 73+(-24)=73-24=49

8/84+(-48)=84-48=36

9/-72-82=-72+(-82)=-154

10/-97-82=-97+(-82)=-179

11/19+(-92)=19-92=-73

12/38-28=10

13/13+(-27)=13-27=-14

14/-85+29=-85-(-29)=-114

15/-84-(-27)=-84+27=-57

16/-23+78=-23-(-78)=-101

17/93+(-29)=93-29=64

18/-74-83=-74+(-83)=-157

19/-183+83=-183-(-83)=-266

20/849-(-3832)=849+3832=4681

Có gì sai mong bạn sửa giúp mình nhé!

ối dồi ôi nhiều thế

mk chịu

đề là gì vậy bạn

1/ -100

2/ 77

3/ 22

4/ 110

5/66

6/-116

7/49

8/36