218-(x+31)=x-29

218-31=x+x-29

2x=218-31+29=218-(31-29)

2x=218-2=216

x=216/2

x=108

29 x (23 +15) - 23x( 29 +15)

= 29 x 23 + 29 x 15 - 23 x 29 - 23 x 15

= ( 29 x 23 - 23 x 29) + 15 x ( 29 - 23)

= 0 + 15 x 6

=90

     \(218-\left(x+31\right)=x-29\)

\(\Leftrightarrow\)\(218-x-31=x-29\)

\(\Leftrightarrow\)\(187-x=x-29\)

\(\Leftrightarrow\)\(2x=216\)

\(\Leftrightarrow\)\(x=108\)

Vậy....

218-(x + 31) = x - 29

=> 218 - x - 31 = x - 29

=> (218-31) - x = x - 29

=> 187 - x = x - 29

=> -x - x = -29 - 187

=> -2x = -216

=> x = -216 : (-2)

=> x = 108

218 - ( x + 31 ) = x - 29

x + 31 + x - 29 = 218

2x + 2 = 218

2x = 218 - 2

2x = 216

  x = 216 : 2

  x = 108

Ta có : 218 - ( x + 81 ) = x - 29

\( \implies\) 218 - x - 81 = x - 29

\( \implies\) 137 - x = x - 29

\( \implies\) 2x = 166

\( \implies\) x = 83 

218 - (x +31)=x - 29

218 - x -31=x-29

218-x=x-29+31

218-x=x+2

x+2=218-x

2=218-x-x

2=218-Xx2

xX2=218-2

Xx2=216

x=216:2

x=108

218 - ( x + 31) = x - 29

<=> 218 - x - 31 = x - 29

<=> -x - x = -29 - 218 + 31

<=> -2x = -216

<=> x = - 108

Vậy x = - 108

khó :v

Bài 1 :

Ta có :

\(-\frac{7}{72}>-\frac{9}{72}\)

\(-\frac{9}{72}>-\frac{9}{40}\)

\(\Rightarrow-\frac{7}{72}>-\frac{9}{40}\)

Vậy \(-\frac{7}{72}>\frac{9}{-40}\)

Bài 2 :

218 - ( x + 3 ) = x - 29

  218 - x - 3    = x - 29

  218 - 3 + 29 = x + x

            2x       = 244

              x       = 122

Vậy x = 122

a) <=> -218 - x - 31 = x - 29

<=> 2x = -220

<=> x = -110

b) <=> -12x + 60 + 21 - 7x = 5

<=> -19x = -76

<=> x = 4

c) <=> 3x + 21 + 28 = 9 - 2x - 10

<=> 5x = -50

<=> x = -10

d) <=> 2x + 6 - 3x + 15 = 12 - 4x - 18

<=> 3x = -27

<=> x = -9

k cho mik

Pt bậc 3 này ko giải được trong chương trình phổ thông