a) Ta có: \(\left(x-1\right)^{x+2}-\left(x-1\right)^{x+4}=0\)

\(\Leftrightarrow\left(x-1\right)^x\cdot\left(x-1\right)^2-\left(x-1\right)^x\cdot\left(x-1\right)^4=0\)

\(\Leftrightarrow\left(x-1\right)^{x+2}\cdot\left[1-\left(x-1\right)^2\right]=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\\x-1=1\\x-1=-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x=2\\x=0\end{matrix}\right.\)

b) Ta có: \(\dfrac{1}{4}\cdot\dfrac{2}{6}\cdot\dfrac{3}{8}\cdot\dfrac{4}{10}\cdot\dfrac{5}{15}\cdot...\cdot\dfrac{30}{62}\cdot\dfrac{31}{64}=2x\)

\(\Leftrightarrow2x=\dfrac{1}{64}\)

hay \(x=\dfrac{1}{128}\)

a, 41-(2x-5)=18

2x-5=41-18

2x=23+5

2x=28

x=28:2

x=14

b,\(2^x.4=128\)

\(2^x=128:4=32\)

\(2^x=2^5\)

=> x=5

c,\(x^{30}=1\)

=>x=1

a) 720:[41-(2x-5)]=8*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

b) x+(x+1)+(x+2)+......+(x+30)=1240

x+x+1+x+2+...+x+30=1240

(x+x+x+....+x) + (1+2+3+....30)=1240

31*x + \(\frac{\left(30+1\right)\cdot30}{2}\)=1240

31*x + 465 =1240

31*x=1240-465

31*x =775

x = 775:31

x=25

tick mình nhé 

CHTT nha bạn ! 

a) - 36 . (16 - 41) - 16 . (41 - 36)

= -36.(-25)-16.5

= 900-80

= 820

b) - 15. (-27 + 30) - 27 . (30 - 15) - 30 . (5 - 27)

= -15.3-27.15-30.(-22)

= -45-405.(-660)

= (-450).(-660)

= 297000

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\(\Leftrightarrow36-2x=36\)

=>x=0

x = 14

720: [41-(2x+5)]=8 x 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   =18

              x   =18:2

             x    =9

\(\Leftrightarrow41-2x+5=720:20=36\)

=>-2x=0

hay x=0

720 : [41 - (2x - 5)] = 2³.5

720 : [41 - (2x - 5)] = 8.5

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

\(720:\left[41-\left(2x-5\right)\right]=2^3\cdot5\)

\(\Rightarrow720:\left(41-2x+5\right)=8\cdot5\)

\(\Rightarrow720:\left(46-2x\right)=40\)

\(\Rightarrow46-2x=720:40\)

\(\Rightarrow46-2x=18\)

\(\Rightarrow2x=46-18\)

\(\Rightarrow2x=28\)

\(\Rightarrow x=28:2\)

\(\Rightarrow x=14\)

`@` `\text {Ans}`

`\downarrow`

`d)`

`720 \div [41 - (2x - 5)] = 2^3 * 5`

`=> 720 \div [41 - (2x - 5)] = 40`

`=> 41 - (2x - 5) = 720 \div 40`

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

`=> 2x - 5 = 41 - 18`

`=> 2x - 5 = 23`

`=> 2x = 23 + 5`

`=> 2x = 28`

`=> x = 28 \div 2`

`=> x = 14`

Vậy, `x = 14.`