25.3-x=104

75-x=104

x=75-104

x=-29

3(5x-15)-52=68

3(5x-15)=68+52

3(5x-15)=120

5x-15=120:3

5x-15=40

5x=40+15

5x=55

x=55:5

x=11

5(x+35)=515

x+35=515:5

x+35=103

x=103-35

x=68

a) (3x+9) (5x-515) =0

Trường hợp 1: 3x+9=0

--> 3x= 0-9

    3x = -9

    x   = -3

Trường hợp 2: 5x - 515 = 0

--> 5x = 0+ 515

     5x = 515

      x= 515 : 5

      x = 103    

a) Vì tích chúng bằng 0 nên phải có ít nhất 1 thừa số bằng 0.

Mà x thuộc n nên 3x + 9 không thể bằng 0. Vậy 5x - 515 = 0. Để 5x - 515 = 0 thì 5x = 515. Suy ra x = 103. Vậy x = 103

b) 100 : [(3x - 5) - 27] = 10

=> (3x - 5) - 27 = 10

=> 3x - 5 = 37

=> 3x = 42

=> x = 14

a) (3x + 9)(5x - 515) = 0

=> 3x + 9 = 0 hoặc 5x - 515 = 0

=> 3x = 9 hoặc 5x = 515

=> x = 3 hoặc x = 103.

b) 100 : [(3x -5) - 27] = 10

=> (3x -5) - 27 = 100 : 10 = 10

=> 3x - 5 = 10 + 27 = 37

=> 3x = 37 + 5 = 42

=> x = 14

a) 12+x=34

          x=34-12

          x=22

b) 23+x=34

         x=34-23

         x=11

c)45+34=79

a, 12 + x = 34

x = 34 - 12

x = 22

b, 23 + x = 34

x = 34 - 23

x = 11

c, 45 + 34 = x 

x = 79

a) 12+x=34

           x=34-12

           x=22

b) 23+x=34

           x=34-23

           x=11

c) 45+23=x

    68=x

    x=68

a)   70 - 5 ( 2x-3 ) = 45

              5( 2x-3 ) = 25

                  2x - 3 = 25 : 5

                 2x - 3  = 5

                       2x = 8 

                         x = 8 : 2

                        x = 4

b)   6 ( 5x + 35 ) = 330

    5x + 35 = 330 : 6

    5x + 35 = 55

            5x = 55 - 35

            5x = 20

              x = 20 : 5

              x = 4 

c)  936 - ( 4x + 24 ) = 72

     4x + 24 = 936 - 72

     4x + 24 = 864

             4x = 864 - 24

             4x = 840

              x = 840 : 4

              x = 210

 d)   5( 3x + 34 ) = 515

             3x + 34 = 515 : 5

             3x + 34 = 103

                     3x = 103 -  34

                     3x = 69

                       x = 69 : 3

                      x = 23

\(a,70-5\left(2x-3\right)=45\)

\(\Leftrightarrow10x-15=70-45\)

\(\Leftrightarrow10x=25+15\)

\(\Leftrightarrow x=\frac{40}{10}=4\)

Vậy x=4

\(b,6\left(5x+35\right)=330\)

\(\Leftrightarrow5x+35=55\)

\(\Leftrightarrow5x=20\)

\(\Leftrightarrow x=4\)

vậy x=4

\(c,936-\left(4x+24\right)=72\)

\(\Leftrightarrow4x+24=936-72\)

\(\Leftrightarrow4x=864-24\)

\(\Leftrightarrow x=840:4=210\)

Vậy x=210

\(d,5\left(3x+34\right)=515\)

\(\Leftrightarrow3x+34=515:5\)

\(\Leftrightarrow3x=103-34\)

\(\Leftrightarrow x=69:3=23\)

Vậy x=23

=>(2x+3).(10x+2)=(5x+2).(4x+5)

=>(2x.10x)+(2x.2)+(3.10x)+(3.2)=(5x.4x)+(5x.5)+(2.4x)+(2.5)

=>20x²+4x+30x+6=20x²+25x+8x+10

=>20x²-20x²+4x-8x+30x-25x=10-6

=>0+4x-8x+30x-25x=4

=>-4x+30x-25x=4

=>26x-25x=4

=>x=4

B)=>(3x-1).(5x-34)=(40-5x).(25-3x)

=>15x²-102x-5x+34=1000-120x-125x+15x²

=>15x²-107x+34=1000-245x+15x²

=>15x²-15x²-107x+245x=1000-34

=>0-107x+245x=966

=>138x=966

=>x=7

A,=>(2x+3).(10x+2)=(5x+2).(4x+5)

=>(2x.10x)+(2x.2)+(3.10x)+(3.2)=(5x.4x)+(5x.5)+(2.4x)+(2.5)

=>20x2+4x+30x+6=20x2+25x+8x+10

=>20x2-20x2+4x-8x+30x-25x=10-6

=>0+4x-8x+30x-25x=4

=>-4x+30x-25x=4

=>26x-25x=4

=>x=4

a) 5x - 14 = x - 34

5x - x = -34 + 14

4x = -20

x = -20 : 4

x = -5

b) x - 3 - (3x + 2) = -15

x - 3 - 3x - 2 = -15

x - 3x = -15 + 3 + 2

-2x = -10

x = (-10) : (-2)

x = 5

c) 2(x  - 12) + 19 = x + (-34)

2x - 24 + 19 = x + (-34)

2x - x = -34 + 24 - 19

x = -29

d) 2(x - 33) - 3(x - 43) = 96 - 115

2x - 66 - 3x + 129 = 96 - 115

2x - 3x = 96 - 115 + 66 - 129

-x = -82

x = 82

e) 2x + 3 - 9x = -11

2x - 9x = -11 - 3

-7x = -14

x = (-14) : (-7)

x = 2

f) -(x + 3 - 84) = (x + 70 - 71) - 6

-x - 3 + 84 = x + 70 - 71 - 6

-x - x = 70 - 71 - 6 - 84

-2x = -91

x = (-91) : (-2)

x = 45,5

kho qua

x^2+5x+6=3x+34+2x

\(x.x+5x-3x-2x=34-6\)

\(x.\left(1+5-3-2\right)=28\)

\(x.1=28\)

\(x=28\)

học tốt