a) 19 + (x - 23) = 50

x - 23 = 50 - 19

x - 23 = 31

=> x  = 31 + 23

     x = 54

b) (273 - x) - 140 = 34

(273 - x) = 34 + 140

(273 - x) = 174

x = 273 - 174

x = 99

c) 56 - (x - 14) = 22

x - 14 = 56 - 22

x - 14 = 34

x = 34 + 14

x = 48

d) 172 - (137 - x) = 93

137 - x = 172 - 93

137 - x = 79

x = 137 - 79

x = 58

e) 13. (x - 14) = 91

x - 14 = 91 : 13

x - 14 = 7

x = 14 + 7

x = 21

g) (13 - x).17 = 51

13 - x = 51 : 17

13 - x = 3

x = 13 - 3

x = 10

chúc bn học giỏi ^^ !

ok mk nha!! ! 5654645645767676576558578779769675634636457567687689978978978978766876765657886567567

1.19+(x-23)=50

<=>x-23=50-19

<=>x-23=31

<=>x=31+23

<=.x=54

vậy x=54

2.(273-x)-140=34

<=>273-x=34+140

<=>273-x=174

<=>x=273-174

<=>x=99(thoả mãn)

vậy x=99

a; \(\dfrac{93}{17}\): \(x\) + (- \(\dfrac{21}{17}\)) : \(x\) + \(\dfrac{22}{7}\): \(\dfrac{22}{3}\) = \(\dfrac{5}{14}\)

   \(\dfrac{94}{17}\) \(\times\) \(\dfrac{1}{x}\) - \(\dfrac{21}{17}\) \(\times\) \(\dfrac{1}{x}\) + \(\dfrac{3}{7}\) = \(\dfrac{5}{14}\)

    \(\dfrac{72}{17}\) \(\times\) \(\dfrac{1}{x}\) + \(\dfrac{3}{7}\) = \(\dfrac{5}{14}\)

     \(\dfrac{72}{17x}\)        = \(\dfrac{5}{14}\) - \(\dfrac{3}{7}\)

      \(\dfrac{72}{17x}\)      = - \(\dfrac{1}{14}\)

      17\(x\)       = 72.(-14)

       17\(x\)     = - 1008

         \(x\)       = - 1008 : 17

         \(x\)       = - \(\dfrac{1008}{17}\)

Vậy \(x\) \(=-\dfrac{1008}{17}\)

b; - \(\dfrac{32}{27}\) - (3\(x\) - \(\dfrac{7}{9}\))³ = - \(\dfrac{24}{27}\)

          - \(\dfrac{32}{27}\)  + \(\dfrac{24}{27}\) = (3\(x\) - \(\dfrac{7}{9}\))³ 

          (3\(x-\dfrac{7}{9}\))³ = - \(\dfrac{8}{27}\)

         (3\(x-\dfrac{7}{9}\))³ = (- \(\dfrac{2}{3}\))³

           3\(x-\dfrac{7}{9}\) = - \(\dfrac{2}{3}\)

           3\(x\)        = - \(\dfrac{2}{3}\) + \(\dfrac{7}{9}\)
           3\(x\)        = \(\dfrac{1}{9}\)

             \(x\)        = \(\dfrac{1}{9}\) : 3

             \(x\)       = \(\dfrac{1}{27}\)

Vậy \(x=\dfrac{1}{27}\)

56 - ( x - 14 ) = 22

x - 14 = 56 - 22

x - 14 = 34

x = 34 + 14

x = 48

172 - ( 137 - x ) = 93

137 - x = 172 - 93

137 - x = 79

x = 137 - 79

x = 58

1/ 56 - (x - 14) = 22  => x - 14 = 56 - 22  => x - 14 = 34  => x = 34 + 14  => x = 48 

2/ 172 - (137 - x) = 93   => 137 - x = 172 - 93   => 137 - x = 79   => x = 137 - 79  => x = 58

=5/9

= 47/5

= 11/18

= 31/15

5/9

47/5

11/18

31/15

4/9 + 7/63 = 28/63 + 7/63 = 35/63
9 + 2/5 = 45/5 + 2/5 = 47/5
17/18 - 3/9 = 17/18 - 6/18 = 11/18
3 - 14/15 = 75/15 - 14/15 = 61/15
LY: Tự rút gọn (nếu cần)

a ) − 13 30 ≤ x < 1 = > x = 0. b ) 5 9 < x ≤ 3 = > x ∈ {1;2;3}

a)  − 2 5 + 1 6 + − 1 5 ≤ x < − 3 4 + 9 7 + − 1 4 + 5 7 ⇔ − 13 30 ≤ x ≤ 1 ⇔ x ∈ 0 ; 1

b)  5 17 + − 4 9 + 12 17 < x ≤ − 3 7 + 7 15 + 4 − 7 + 8 15 + 9 3 ⇔ 5 9 < x ≤ 3 ⇔ x ∈ 1 ; 2 ; 3