\(\dfrac{37}{17}+\dfrac{31}{17}< x\le\dfrac{50}{18}.\dfrac{38}{25}\)

\(4< x\le4\dfrac{2}{9}\)

⇒x=∅

⇔68/17<x≤38/9

⇔4<x≤\(4\dfrac{2}{9}\)

a) \(\dfrac{25}{37}\times\dfrac{18}{29}+\dfrac{18}{29}\times\dfrac{12}{37}\)

\(=\dfrac{18}{29}\times\left(\dfrac{25}{37}+\dfrac{12}{37}\right)\)

\(=\dfrac{18}{29}\times\dfrac{37}{37}\)

\(=\dfrac{18}{29}\times1\)

\(=\dfrac{18}{29}\)

b) \(\dfrac{31}{85}\times\dfrac{11}{19}+\dfrac{31}{85}\times\dfrac{12}{19}-\dfrac{42}{19}\times\dfrac{31}{85}\)

\(=\dfrac{31}{85}\times\left(\dfrac{11}{19}+\dfrac{12}{19}-\dfrac{42}{19}\right)\)

\(=\dfrac{31}{85}\times\dfrac{-19}{19}\)

\(=\dfrac{31}{85}\times-1\)

\(=-\dfrac{31}{85}\)

c) \(\dfrac{16}{53}:\dfrac{17}{9}-\dfrac{16}{53}:\dfrac{17}{8}\)

\(=\dfrac{16}{53}:\left(\dfrac{9}{17}-\dfrac{8}{17}\right)\)

\(=\dfrac{16}{53}:\dfrac{1}{17}\)

\(=\dfrac{16}{901}\)

c) \(\dfrac{1}{5}\times\dfrac{12}{31}\times\dfrac{4}{3}+\dfrac{19}{31}\times\dfrac{4}{15}\)

\(=\dfrac{4}{15}\times\dfrac{12}{31}+\dfrac{19}{31}\times\dfrac{4}{15}\)

\(=\dfrac{4}{15}\times\left(\dfrac{12}{31}+\dfrac{19}{31}\right)\)

\(=\dfrac{4}{15}\times\dfrac{31}{31}\)

\(=\dfrac{4}{15}\times1\)

\(=\dfrac{4}{15}\)

a: =18/29*(25/37+12/37)

=18/29

b: =31/85(11/19+12/19-42/19)

=-31/85

c; =16/53(9/17+8/17)=16/53

d: =4/15(12/31+19/31)=4/15

PT \(\Leftrightarrow x-29-17+38=-9\)

\(\Leftrightarrow x=-9-38+17+29=-1\)

Vậy ...

( x - 29 ) - ( 17 - 38 ) = - 9

x-29-17+38=-9

x=-9+29+17-38

x=-1

\(\left(x-29\right)-\left(17-38\right)=-9\)

\(\left(x-29\right)+21=-9\)

\(x-29=-30\)

\(x=-1\)

\(\left(x-29\right)-\left(17-38\right)=-9\\ \left(x-29\right)-\left(-21\right)=-9\\ x-29+21=-9\\ x-29=-9-21\\ x-29=-30\\ x=-30+29\\ x=-1\)

e: =>-40+3+33+40-x=47

=>36-x=47

=>x=-11

f: =>x(x-3)(11-x)(11+x)=0

hay \(x\in\left\{0;3;11;-11\right\}\)

g: =>-62-38-x+2x=-100

=>x-100=-100

hay x=0

i: =>x-12-2x-31=6

=>-x-43=6

=>x+43=-6

hay x=-49

h: =>(x+1)=0

=>x=-1

f: =>x(x-3)(x+11)(x-11)=0

hay \(x\in\left\{0;3;-11;11\right\}\)

9. Tìm x biết 

a x- ( 12- 15)= -8

<=> x - 12 + 15 = -8

<=> x + 3 = -8

<=> x = -11

Vậy x = -11

b. (x- 29 )- ( 17- 38)= -9

<=> x - 29 - 17 + 38 = -9

<=> x - 8 = -9

<=> x = -1

Vậy x = -1

a) x-12+15=-8

=>x=-8-15+12

=>x=-11

Vậy x=-11

b)x-29+21=-9

=>x=-9-21+29

=>x=-1

Vậy x=-1

a) Ta có: x-(12-15)=-8

\(\Leftrightarrow x-12+15=-8\)

\(\Leftrightarrow x+3=-8\)

hay x=-8-3=-11

Vậy: x=-11

b) Ta có: \(\left(x-29\right)-\left(17-38\right)=-9\)

\(\Leftrightarrow x-29-17+38+9=0\)

\(\Leftrightarrow x+1=0\)

hay x=-1

Vậy: x=-1

\((x-29)-(17-38)=-9\\ \Leftrightarrow x - 29 - (-21) = -9\\ \Leftrightarrow x - 8 = - 9\\ \Leftrightarrow x = - 1\)

(x - 29) - (17 - 38) = - 9

\(\Leftrightarrow\) x - 29 - 17 + 38 = - 9

\(\Leftrightarrow\)x - 8 = - 9 

\(\Leftrightarrow\)x = - 1

Vậy x = - 1

(x-29) -(17-38)=-9

     x-29 - (-21)=-9

    x-29 + 21=-9

           x-29 =-9 -21

          x-29 = - 12

               x =-12 + 29

                x= 7

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