Ta có 

72+36.2+18.2.6

=36.2+36.2+36.6

=36.(2+2+6)

=36.10

=360 

Dấu . là nhân nha

        (x+40)x25=2000

=>    x+40=2000:25

=>    x+40=80

=>    x=80-40

=>   x=40

Vậy x=40

      (x-10)x5=100-20x4

=>  (x-10)x5=100-80

=>  (x-10)x5=20

=>   x-10=20:5

=>   x-10=4

=>   x=4+10

=>   x=14

Vậy x=14

      x:2x36=540

=>  x:2=540:36

=>  x:2=15

=>  x=15x2

=>  x=30  

Vậy x=30

      (72x135+9x28x15):25-3500:25

=    (72x135+135x28):25-3500:25

=     135x(72+28):25-3500:25

=     135x100:25-3500:25

=     13500:25-3500:25

=     (13500-3500):25

=     10000:25

=      400

Ai cùng đáp án thì tk và kb vs mk nha !!! Mk cảm ơn nhìu >.<

(x+40) nhân 25= 2000

(x+40)= 2000: 25

x+40= 80

x=80-40

x= 40

(x-10) nhân 5= 100- 20 nhân 4

(x-10) nhân 5= 20

(x-10) =20:5

x-10= 4

x=4+10

x=14

x:2x 36=540

x:2= 540:36

x:2=15

x= 15x 2

x= 30

(72x 135+ 9x 28x 15) : 25- 3500: 25

(72x 135+ 135x 28): 25- 3500:25

((72+28) x135): 25-3500: 25

100x 135: 25- 3500:25

13500: 25- 3500: 25

( 13500-3500) : 25

10000: 25

400

nha bn

=   5544   

 k cho mk

=5544

tk minh nha

540

=1166400 : 2160

=540

36 x 5 + 72 x 2 - 216 + 144

= 252

\(36\text{×}5+72\text{×}2-216+144\)

\(=36\text{×}5+36\text{×}2\text{×}2-36\text{×}6+36\text{×}4\)

\(=36\text{×}5+36\text{×}4-36\text{×}6+36\text{×}4\)

\(=36\text{×}\left(5+4-6+4\right)=36\text{×}7=252\)

117 x 36 + 117 x 72 - 17 x 72 - 17 x 36

= ( 117 - 17 ) x 36 - ( 117 - 17 ) x 72

= 100 x 36 - 100 x 72

= 100 x ( 36 - 72 )

= 100 x -36

 = -3600

____________________________________

408 x 53 - 5 x 204 - 204

= 408 x 53 - 5 x 204 - 204 x 1

= 408 x 53 - ( 5 - 1 ) x 204

= 408 x 53 - 4 x 204

= 21624 - 816

= 20808

Cảm ơn bạn Đinh Chí Công

a: \(=68\cdot72\cdot49\cdot\left[324-324\right]=0\)

b: \(=\left(1250-1250\right)\cdot\left(1+...+100\right)=0\)

\(a,\left(68\times72\times49\right)\times\left(27\times12-9\times36\right)=\left(68\times72\times49\right)\times0=0\\ b,\left(25\times50-125\times10\right)\times\left(1+2+...+100\right)=0\times\left(1+2+...+100\right)=0\)

có sai đề ko ạ?

Sửa đề:
\(72\times26+26\times28\)
\(=\left(72+28\right)\times26\)
\(=100\times26\)
\(=2600\)