Question

tìm số tự nhiên x , biết :

1) 58 + 7x=100

2)(x-12):12=12

3)x-56:4=16

4) 101+(36-4x)=105

5)2(x-51)=2.2 mũ 3 + 20

dạng bài khá khó nên cẩn thân khi làm nha ^-^

Answer 1

`#3107.101107`

`1)`

`58 + 7x = 100`

`=> 7x = 100 - 58`

`=> 7x = 42`

`=> x = 42 \div 7`

`=> x = 6`

Vậy, `x = 6`

`2)`

`(x - 12) \div 12 = 12`

`=> x - 12 = 12*12`

`=> x - 12 = 144`

`=> x = 144 + 12`

`=> x = 156`

Vậy, `x = 156`

`3)`

`x - 56 \div 4 = 16`

`=> x - 14 = 16`

`=> x = 16 + 14`

`=> x = 30`

Vậy, `x = 30`

`4)`

`101 + (36 - 4x) = 105`

`=> 36 - 4x = 105 - 101`

`=> 36 - 4x = 4`

`=> 4x = 36 - 4`

`=> 4x = 32`

`=> x = 32 \div 4`

`=> x = 8`

Vậy, `x = 8`

`5)`

`2(x - 51) = 2*2^3 + 20`

`=> 2(x - 51) = 2^4 + 20`

`=> 2(x - 51) = 16 + 20`

`=> 2(x - 51) = 36`

`=> x - 51 = 36 \div 2`

`=> x - 51 = 18`

`=> x = 18 + 51`

`=> x = 69`

Vậy, `x = 69.`

Answer 2

1) 58 + 7x=100

             7x = 100 - 58

             7x = 42

              x = 42 : 7

              x = 6

2)(x-12):12=12

    (x - 12) = 12 x 12

    x - 12   = 144

     x          = 144 + 12

      x =  156

3)x-56:4=16

   x - 14 = 16

    x       = 16 + 14

    x       = 30

4) 101+(36-4x)=105

             (36-4x) = 105 - 101

              36-4x  =   4

                     4x = 36 - 4

                      4x = 32

                        x = 32 : 4

                        x = 8

5)2(x-51)=2.2 mũ 3 + 20

    2(x-51)=2.8 + 20

     2(x-51)=16 + 20

     2(x-51)= 36

        x - 51 = 36 : 2

         x - 51 = 18

         x = 18 + 51

         x = 69

Answer 3

1: 7x+58=100

=>\(7x=100-58=42\)

=>\(x=\dfrac{42}{7}=6\)

2: \(\left(x-12\right):12=12\)

=>\(x-12=12\cdot12=144\)

=>x=156

3: \(x-56:4=16\)

=>\(x-14=16\)

=>x=30

4: \(101+\left(36-4x\right)=105\)

=>36-4x=4

=>4x=32

=>x=8

5: \(2\cdot\left(x-51\right)=2\cdot2^3+20\)

=>\(2\left(x-51\right)=16+20=36\)

=>x-51=18

=>x=69