\(a,4^8.2^{20}=\left(2^2\right)^8.2^{20}=2^{16}.2^{20}=2^{16+20}=2^{36}\\ b,9^{12}.27^5.81^4=\left(3^2\right)^{12}.\left(3^3\right)^5.\left(3^4\right)^4=3^{24}.3^{15}.3^{16}=3^{24+15+16}=3^{55}\\ d,25^{20}.125^4=\left(5^2\right)^{20}.\left(5^3\right)^4=5^{40}.5^{12}=5^{40+12}=5^{52}\\ d,x^7.x^4.x^3=x^{7+4+3}=x^{14}\)

a: 4*8*2^20=2^2*2^3*2^20=2^25

b: 9^12*27^5*81^4=3^24*3^15*3^16=3^55

c: 25^20*125^4=5^40*5^12=5^52

d: =x^(7+4+3)=x^14

Bài 1: Tính hợp lí:

a) (-81 -124) -(76 -81)

   = -81 -124 - 76 +81

   = (-81 + 81) - (124 + 76)

  = 0 - 200 = -200

b) 1009 - (1009 +111) -89

  = 1009 - 1009 - 111 -89

  = (1009 - 1009) - ( 111 +89)

  = 0 - 200 = -200

c) (-247 +63) -(63 - 247)

  = -247 + 63 -63 + 247

  = (-247 +247) + (63-63)

  = 0+0 =0

d) 1254 - (459 - 1254) - 541

  = 1254 - 459 + 1254 - 541

  = (1254+1254) - (459 + 541)

  = 2508 - 1000 = 1508

Bài 2: Tìm x

a)x - 148 - 2x - 150

  (x-2x) - (148 + 150) = ?

  -1x - 298 = ?

  -1x = ? + 298

 .... Từ đó tự giải tiếp

b)15 - (10-2x)-x-29

  15 - 10 + 2x -x - 29 =?

  (15-10-29) + (2x -x) =?

  (-24) + x =?

  x = ? + 24

  ... Từ đó tự giải tiếp

c) ( -2x + 12) -(3x -14)= (6x +1)+ (-12x -17)

  -2x + 12 - 3x + 14 = 6x + 1 - 12x - 17

  (-2x - 3x) + ( 12 + 14) = (6x - 12x) + (1-17)

  (-5x) + 26= (-6x) + (-16)

  (-5x) + 6x = (-16) - 26

   x = -42

Chúc bạn học tốt ! ^^ ~~~

a)\(16^6:4^2=\left(4^2\right)^6:4^2=4^{12-2}=4^{10}\)

b)\(18^8:9^4=\left(2.9\right)^8:9^4=2^8.9^8:9^4=2^8.9^4=\left(2^2.9\right)^4=36^4\)

c)\(125^4:25^3=\left(5^3\right)^4:\left(5^2\right)^3=5^{12}:5^6=5^6\)

d)\(12^n:2^{2n}=\left(2^2.3\right)^n:2^{2n}=2^{2n}.3^n:2^{2n}=3^n\left(n\inℕ^∗\right)\)

bạn chơi liên quân à

Tìm x

ko

1254.1252-4/1251.1255-1

= 1254.(1251+1)-4/1251.(1254+1)-1

= 1254.1251+1254-4/1251.1254+1251-1

= 1254.1251+1250/1251.1254+1250

= 1

1)

`x^2 -144=0`

`<=> x^2 =144`

\(< =>\left[{}\begin{matrix}x=12\\x=-12\end{matrix}\right.\)

2)`

`2x^2 -72=0`

`<=>2x^2 =72`

`<=>x^2=36`

\(< =>\left[{}\begin{matrix}x=6\\x=-6\end{matrix}\right.\)

3)

`5x^2 -125=0`

`<=> 5x^2 =125`

`<=>x^2 =25`

\(< =>\left[{}\begin{matrix}x=5\\x=-5\end{matrix}\right.\)

4)

`-x^2 +81=0`

`<=> x^2 -81=0`

`<=> x^2 =81`

\(< =>\left[{}\begin{matrix}x=9\\x=-9\end{matrix}\right.\)

5)

`x(2x-18)=0`

\(< =>\left[{}\begin{matrix}x=0\\2x-18=0\end{matrix}\right.\\ < =>\left[{}\begin{matrix}x=0\\x=9\end{matrix}\right.\)

tìm nghiệm của đa thức ạ

4

2499

540

1 + 1 + 1 + 1 = 4

1254 + 1245 = 2499

540 : 10 x 10 = 540

= 4

= 2499 

= 540 

k nha ! 

b)   \(-2x+\left(-3x\right)+\left(-4x\right)+......+\left(-20x\right)=1254\)

\(\Rightarrow x.\left(-2-3-4-.......-20\right)=1254\)

\(\Rightarrow x.\left[-\left(2+3+4+.....+20\right)\right]=1254\)

\(\Rightarrow x.\left(-209\right)=1254\)

\(\Rightarrow x=1254:\left(-209\right)\)

\(\Rightarrow x=-6\)

c)   \(\left|2x\right|=4\)

\(\Rightarrow\orbr{\begin{cases}2x=4\\2x=-4\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=2\\x=-2\end{cases}}\)

d)   \(\left|2x-1\right|=3\)

\(\Rightarrow\orbr{\begin{cases}2x-1=3\\2x-1=-3\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}2x=4\\2x=-2\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=2\\x=-1\end{cases}}\)

Cảm ơn nha ~