a, 128 – 3(x+4) = 23

b,  12 x - 4 3 . 8 3 = 4 . 8 4

c, [(4x+28).3+55]:5 = 35

d, 720:[41 – (2x – 5)] =  2 3 . 5

a,

128-3x-12=23

3x=128-12-23

3x=93

x=93:3

= 31

b,

(12x+84+55):5=35

12x+84+55=35.5

12x+84+55=175

12x=175-55-84

12x=36

x=36:12

x=3

\(a,128-3.\left(x+4\right)=23\\ \Rightarrow3.\left(x+4\right)=105\\ \Rightarrow x+4=35\\ \Rightarrow x=31\\ b,\left[\left(4x+28\right).3+55\right]:5=35\\ \Rightarrow\left(4x+28\right).3+55=175\\ \Rightarrow4x+28.3=120\\ \Rightarrow4x+28=60\\ \Rightarrow4x=32\\ \Rightarrow x=8.\)

c) \(\left(12x-4^3\right).8^3=4.8^4\)

\(12x-64=4.8^4:8^3\)

\(12x-64=32\)

\(12x=32+64\)

\(12x=96\)

\(x=\dfrac{96}{12}\)

\(x=8\)

d) \(720:\left[41-\left(2x-5\right)\right]:5=35\)

\(720:\left(41-2x+5\right):5=35\)

\(720:\left(46-2x\right)=35.5\)

\(720:\left(46-2x\right)=175\)

\(46-2x=720:175\)

\(46-2x=\dfrac{144}{35}\)

\(2x=46-\dfrac{144}{35}\)

\(2x=\dfrac{1466}{35}\)

\(x=\dfrac{1466}{35}:2\)

\(x=\dfrac{733}{35}\)

lm nốt hộ mik 2 ý cuối vs ạ

a: =>3(x+4)=115

=>x+4=115/3

hay x=103/3

b: =>\(8^3\cdot\left(12x-64\right)=4\cdot8^4\)

\(\Leftrightarrow12x-64=32\)

=>12x=96

hay x=8

c: \(\Leftrightarrow\left(4x+28\right)\cdot23+55=175\)

=>(4x+28)x23=120

=>4x+28=120/23

=>4x=-524/23

hay x=-131/23

128-3.(x+4) =23                 

        3.(x+4) =128-23

        3.(x+4) = 105

            x+4 =105:3

            x+4 =35

               x = 35-4

               x=31

4.x + 5.x -x =128

a)120-3(x+4)=23

=>3(x+4)=120-23

=>3(x+4)=97

=>x+4=97:3

=>x+4=\(\frac{97}{3}\)

=>x=\(\frac{97}{3}\)-4

=>x=\(\frac{85}{3}\)

Vậy x=\(\frac{85}{3}\)

b)[(4x+28).3+55]:5=35

=>(4x+28).3+55=35.5

=>(4x+28).3+55=175

=>(4x+28).3=175-55

=>(4x+28).3=120

=>4x+28=120:3

=>4x+28=40

=>4x=40-28

=>4x=12

=>x=12:4

=>x=3

Vậyx= 3

c)\((12x-4^3).8^3=4.8^4\)

=>\(12x-64=4.8^4:8^3\)

=>12x-64=4.8

=>12x-64=32

=>12x=96

=>x=96:12

=>x=8

Vậy x=8

d)720:[41-(2x-5)]=2³.5

=>720:[41-2x-5)]=40

=>41-(2x-5)=720:40

=>41-(2x-5)=18

=>2x-5=41-18

=>2x-5=23

=>2x=23+5

=>2x=28

=>x=28:;2

=>x=14

Vậy x=14

a, 120 - 3 [ x+4]=23

     3 [x+4]= 120-23 = 97

      3x = 97-4

      3x= 93

        x= 93:3

        x=31

em bt làm mỗi bài này thui mà ko bt đúng ko

a) 120 - 3(x + 4) = 23

=> 3(x + 4) = 120 - 23 = 97

=> x + 4 = 97 : 3

=> x + 4 = 97/3

=> x = 97/3 - 4 = 85/3

b) [(4x + 28) . 3 + 55] : 5 = 35

=> [(4x + 28) . 3 + 55] = 175

=> (4x + 28).3 + 55 = 175

=> (4x + 28).3 = 120

=> 4x + 28 = 40

=> 4x = 12

=> x = 3

c) (12x - 4³).8³ = 4.8⁴

=> (12x - 4³) = \(\frac{4\cdot8^4}{8^3}=4\cdot8=32\)

=> 12x - 64 = 32

=> 12x = 96

=> x = 96 : 12 = 8

d) Tương tự

a) 3x² + 12x =0

<=> 3x( x+ 4)=0

<=> \(\orbr{\begin{cases}3x=0\\x+4=0\end{cases}}\) <=>\(\orbr{\begin{cases}x=0\\x=-4\end{cases}}\) 

d) \(4x^3=4x\)

<=> \(4x^3-4x=0\) 

<=> 4x( x² -1) =0

<=> 4x ( x - 1) ( x+ 1) =0

<=> 4x=0 hoac x-1=0 hoac x+1=0

<=> x=0 hoac x=1 hoac x=-1