\(\frac{2^{12}\cdot13+68\cdot8^4}{4^6\cdot3^3}\)

\(=\frac{2^{12}\cdot13+68\cdot2^{12}}{2^{12}\cdot27}\)

\(=\frac{2^{12}\left(13+68\right)}{2^{12}\cdot27}\)

\(=\frac{81}{27}\)

=3

a) (12 + 8) x 4 = 20 x 4

                         = 80

12 + 8 x 4 = 12 + 32

                         = 44

b) 25 + 75 : 5 = 25 + 15

                         = 40

(25 + 75) : 5 = 100 : 5

                         = 20

a: Ta có: \(N=\dfrac{x^3-1}{x^2-2x+1}\)

\(=\dfrac{\left(x-1\right)\left(x^2+x+1\right)}{\left(x-1\right)^2}\)

\(=\dfrac{x^2+x+1}{x-1}\)

\(=\dfrac{\left(-1\right)^2+\left(-1\right)+1}{-1-1}=\dfrac{1}{-2}=-\dfrac{1}{2}\)

b: Ta có: \(M=\dfrac{x^3+8}{x^2-2x+4}\)

\(=\dfrac{\left(x+2\right)\left(x^2-2x+4\right)}{x^2-2x+4}\)

\(=x+2=0\)

a) \(N=\dfrac{x^3-1}{x^2-2x+1}=\dfrac{\left(x-1\right)\left(x^2+x+1\right)}{\left(x-1\right)^2}=\dfrac{x^2+x+1}{x-1}=\dfrac{\left(-1\right)^2-1+1}{-1-1}=-\dfrac{1}{2}\)b) \(M=\dfrac{x^3+8}{x^2-2x+4}=\dfrac{\left(x+2\right)\left(x^2-2x+4\right)}{x^2-2x+4}=x+2=-2+2=0\)

\(\dfrac{10.4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}=\dfrac{5.2.2^{12}.3^{10}+3^9.2^9.2^3.3.5}{2^{12}.3^{12}-2^{11}.3^{11}}\)

\(=\dfrac{5.2^{13}.3^{10}+2^{12}.3^{10}.5}{2^{11}.3^{11}\left(2.3-1\right)}=\dfrac{2^{12}.3^{10}.5\left(2+1\right)}{2^{11}.3^{11}.5}\)

\(=\dfrac{2^{11}.2.3^{10}.5.3}{2^{11}.3^{10}.3.5}=2\)

Bài 2: 

a: =47,4+47,4x4=47,4x5=237

b: =(0,26+0,74)+(0,41+0,59)=1+1=2

Tính bằng cách thuận tiện ( đề `b` )

`13/50+74/100+41/100+59/100`

`=>` `26/100+74/100+41/100+59/100`

`=>` `(26/100+74/100) + ( 41/100 + 59/100)`

`=>` `1+1`

`=>` `2`

Bài 3: 

a: =>x=13-24=-11

b: =>3x=12

hay x=4

a) A = 4 + 4 + 8 + 16 + ...... + 1048576

2A = 8 + 8 + 16 + ...... + 1048576 + 2.1048576

2A - A = (8 + 8 + 16 + ...... + 1048576 + 2.1048576) - (4 + 4 + 8 + 16 + ...... + 1048576)

A = 2.1048576 + 8 - 4 - 4

A = 2.1048576 = 2097152

b) (x + 1) + (x + 2) + ...... + (x + 100) = 5750

x + 1 + x + 2 + ...... + x + 100 = 5750

100x + (1 + 2 + 3 + ..... + 100) = 5750

Ta có : 

1 + 2 + 3 + ..... + 100 = 5050

=> 100x + 5050 = 5750

=> 100x = 200

=> x = 2