a) (37 – 18) + 17 = 19 + 17 = 36

b) 56 – (35 – 16) = 56 – 19 = 37

c) (6 + 5) x 8 = 11 × 8 = 88

d) 36 : (62 – 56) = 36 : 6 = 6

\(a,\sqrt{x}=3\Leftrightarrow x=9\\ b,\sqrt{x}=6\Leftrightarrow x=36\\ c,\sqrt{x}=8\Leftrightarrow x=64\\ d,\sqrt{x}=12\Leftrightarrow x=144\\ e,2\sqrt{x}=10\Leftrightarrow\sqrt{x}=5\Leftrightarrow x=25\\ f,3\sqrt{x}=21\Leftrightarrow\sqrt{x}=7\Leftrightarrow x=49\\ g,\sqrt{x}=8\Leftrightarrow x=64\\ h,2+\sqrt{x}=11\Leftrightarrow\sqrt{x}=9\Leftrightarrow x=81\)

a. \(\sqrt{x}=3\)

<=> \(\left(\sqrt{\sqrt{x}}\right)^2-\left(\sqrt{3}\right)^2=0\)

<=> \(\left(\sqrt{\sqrt{x}}-\sqrt{3}\right)\left(\sqrt{\sqrt{x}}+\sqrt{3}\right)=0\)

<=> \(\left[{}\begin{matrix}\sqrt{\sqrt{x}}-\sqrt{3}=0\\\sqrt{\sqrt{x}}+\sqrt{3}=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=9\\x=\left(Vnghiêm\right)\end{matrix}\right.\)

Vậy nghiệm của PT là S = \(\left\{9\right\}\)

a) \(\sqrt{x}=3\Leftrightarrow x=9\)

b) \(\sqrt{x}=6\Leftrightarrow x=36\)

c) \(\sqrt{x}=8\Leftrightarrow x=64\)

d) \(\sqrt{x}=12\Leftrightarrow x=144\)

e) \(2\sqrt{x}=10\Leftrightarrow\sqrt{x}=5\Leftrightarrow x=25\)

f) \(3\sqrt{x}=21\Leftrightarrow\sqrt{x}=7\Leftrightarrow x=49\)

g) \(\sqrt{x}=8\Leftrightarrow x=64\)

h) \(2+\sqrt{x}=11\Leftrightarrow\sqrt{x}=9\Leftrightarrow x=81\)

a, (x + 30) – 75 = 125

=> x + 30 = 125 + 75 = 200

=> x = 200 – 30

=> x = 170

Vậy x = 170

b, x – 72 : 36 = 18

=> x – 2 = 18

=> x = 18 + 2 = 20

Vậy x = 20

c, x – 17 = 54

=> x = 54 +17

=> x = 71.

Vậy x = 71

d, 36 – (x – 2) = 12

=> x – 2 = 36 – 12

=> x = 24 + 2 = 26

Vậy x = 26

e, 9x – 7 = 837

=>9x = 837 + 7 = 844

=> x =  844 9

Vậy x =  844 9

f, (x – 15) – 107 = 0

=> x – 15 = 107

=> x = 107 +15

=> x = 122.

Vậy x = 122

g, 134 + (116 – x) = 145

=> 116 – x = 145 – 134

=> x = 116 – 11

=> x = 5.

Vậy x = 5

Có ngay nè e

a. X x 36 =972

    X = 972 : 36

    X = 27

b. ( X - 47) x 21 = 840

     X - 47 = 840 : 21

     X - 47 = 40

     X = 40 + 47

      X = 87

c. X x 22 + X x 50 = 504

   X x ( 22 + 50) = 504

   X x       72        = 504'

   X                      = 504 : 72

    X                     =      7

d.254 : x = 14 ( dư 16)

             X = ( 254 - 16) : 14

             X =       238      : 14

               X = 17

e. 729 : X = 81

              X = 729 : 81

              X =     9

f. y x 15 + y x 13 = 560 x 45

   y x 15 + y x 13 =  25 200

  y x ( 15 + 13 )   = 25 200

   y x      28         = 25 200

    y                     = 25 200 : 28

     y                   = 900

Có sai ở đâu thông cảm cho a nhé, Dài quá e ạ

30,31

36+1

20

88

Bài 23: Tìm x:

a) 29 < 30 < 32

b) 36 < 37 + 1 < 39

c) 30 + 30 < 64

d) 46 < 88 - 42 < 48

a, 30

b,37

c, 30

d, 88

a) x * 2 + x * 3 = 60

x * ( 2 + 3 ) = 60

x = 60 : 5

x = 12

b) x * 15 - x * 9 = 78

x * ( 15 - 9 ) = 78

x = 78 : 6

x = 13

a: Ta có: \(3\left(2x-3\right)+2\left(2-x\right)=-3\)

\(\Leftrightarrow6x-9+4-2x=-3\)

\(\Leftrightarrow4x=2\)

hay \(x=\dfrac{1}{2}\)

a: =>x+61=74

hay x=13

b: =>x-35=120

hay x=155

d: =>7x=721

hay x=103

b) Ta có: \(x-43=\left(57-x\right)-50\)

\(\Leftrightarrow x-43=57-x-50\)

\(\Leftrightarrow x+x=7+43\)

\(\Leftrightarrow2x=50\)

hay x=25

Vậy: x=25

c) Ta có: (x-2)(8-x)=0

\(\Leftrightarrow\left[{}\begin{matrix}x-2=0\\8-x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=8\end{matrix}\right.\)

Vậy: \(x\in\left\{2;8\right\}\)