a: Ta có: \(100-7\left(x-5\right)=58\)

\(\Leftrightarrow7\left(x-5\right)=42\)

\(\Leftrightarrow x-5=6\)

hay x=11

b: Ta có: \(12\left(x-1\right):3=4^3+2^3\)

\(\Leftrightarrow12\left(x-1\right)=216\)

\(\Leftrightarrow x-1=18\)

hay x=19

Hoctot

\(5.\left(x-1\right)-206=2^4.4\\ \Rightarrow5.\left(x-1\right)-206=16.4\\ \Rightarrow5.\left(x-1\right)-206=64\\ \Rightarrow5.\left(x-1\right)=270\\ \Rightarrow x-1=54\\ \Rightarrow x=55.\)

5.(\(x-1\)) - 206 = 2⁴.4

5.(\(x-1\))  - 206 = 64

5.(\(x-1\))            = 64 + 206

5.(\(x-1\)) = 270

    \(x-1\)   = 270 : 5

    \(x-1\)   = 54

    \(x=55\)

D

B

12

3

D
B
12
3

Yêu cầu là gì v c.

Phương thức đa thức thành nhân tử ạ

a)100-7.[x-5]=58

          7.[x-5]=100-58=42

               x-5=42:7=6

                  x=6+5

                  x=11

b)12.[x-1]:3=4³+2³

   12 [x-1]:3=64+8

   12.[x-1]:3=72

        [x-1]:3=72:12=6

           [x-1]=6.3=18

                x=18-1

                x=17

tao koooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo biếtttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt

a, 100 - 7 ( x - 5 ) = 31 + 3³

100 - 7 ( x - 5 ) = 31 + 27

100 - 7 ( x - 5 ) = 58

7 ( x - 5 ) = 100 - 58

7 ( x - 5 ) = 42

x - 5 = 42 : 7

x - 5 = 6

=> x = 6 +5

=> x = 11

Vậy x = 11

b, 12 ( x - 1 ) : 3 = 4³ + 2³

12 ( x - 1 ) : 3 = 64 + 8

12 ( x - 1 ) : 3 = 72

12 ( x - 1 ) = 72 . 3

12 ( x - 1 ) = 216

x - 1 = 216 : 12

x - 1 = 18

=> x = 18 + 1

=> x = 19

Vậy x = 19

c, 24 + 5x = 7⁵ : 7³

24 + 5x = 7²

24 + 5x = 49

5x = 49 - 24

5x = 25

=> x = 25 : 5

=> x = 5

Vậy x = 5

d, 5x - 206 = 2⁴ . 4

5x - 206 = 16 . 4

5x - 206 = 64

5x = 64 + 206

5x = 270

=> x = 270 : 5

=> x = 54

Vậy x = 54

e, 125 = x³

5³ = x³

=> x = 5

Vậy x = 5

g, 64 = x²

8² = x²

=> x = 8

Vậy x = 8

Câu 1: B

Câu 2: C

\(4x\left(x^2-5x+3\right)=4x^3-20x^2+12x\)

=> Chọn A