a ) 18^2 : 9^2 .2^2 +12-12:3

= 4^2 :3 = 16/3

b) 5! +2^10 :2^8

= 120 + 4 = 124

c)28 :[ 117 - ( 117- 4) ] . 7 + 5^3 :125

= 28 : 4 * 7 + 1 = 50

d)3^3. 3^5.3 +2^7 :64

= 3^9 + 2^7 : 2^6 = 3^9 + 1 (tính nhé)

bài 2: tìm x thuôc N biết 

a) (2x -2^5). 5^3=2^3.5^3

2x - 2^5 = 2^3 

2x = 40 

x=20

b) 2^2x -4= 72:3^2

2^2 * x = 12 

x= 3

c)3^x + 3^x+1 =108

\(3^x+3^{x+1}=108\) (là thế này ak??)

3^x (1+3) = 108

3^x = 27

x=3 

d)(x -3).(3x+5) =0

\(\Rightarrow\orbr{\begin{cases}x-3=0\\3x+5\end{cases}\Rightarrow\orbr{\begin{cases}x=3\\x=-\frac{5}{3}\end{cases}}}\)

\(=\dfrac{117}{18}\left(\dfrac{1}{6}+\dfrac{1}{3}+\dfrac{1}{2}\right)=\dfrac{117}{18}\)

\(\dfrac{117}{118}\)

\(\dfrac{117}{118}\times\dfrac{1}{6}+\dfrac{117}{118}\times\dfrac{1}{3}+\dfrac{117}{236}\)

\(=\dfrac{117}{118}\times\dfrac{1}{6}+\dfrac{117}{118}\times\dfrac{1}{3}+\dfrac{117}{118}\times\dfrac{1}{2}\)

\(=\dfrac{117}{118}\left(\dfrac{1}{6}+\dfrac{1}{3}+\dfrac{1}{2}\right)\)

\(=\dfrac{117}{118}\times1=\dfrac{117}{118}\)

-2 nhé bạn

                  (3.5+5.7)x+(3.5+5.7)+(3.5+5.7)=0

                       9.2x + 9.2 +9.2 = 0

                       9.2x +9.1 x 1 + 9.2 x 1 = 0

                      9.2( x + 1 + 1 ) = 0

                      9.2(x+2)=0

                           x + 2 = 0 : 9.2 

                           x + 2 = 0 

                           x = 0 - 2 

                           x = -2

\(\left(3.5+5.7\right)x+\left(3.5+5.7\right)+\left(3.5+5.7\right)=0\)

\(\left(3.5+5.7\right)^3.x=0\)

\(125000.x=0\)

\(\Leftrightarrow x=0\)

45 x ( 55 + 117 ) + 55 x ( 117 - 45 )

= (45 x 55 - 45 x 55) + (45 + 55) x 117

= 0  + 100 x 117 = 11700

\(45\times\left(55+117\right)+55\times\left(117-45\right)\)

\(=45\times55+45\times117+55\times117-55\times45\)

\(=\left(45\times55-45\times55\right)+45\times117+55\times117\)

\(=45\times117+55\times117\)

\(=117\times\left(45+55\right)\)

\(=117\times100\)

\(=11700\)

a, 21075200

b, 7384000

c,10530

a) 2368 x 125 + 2368 x 8775

= 2368 x ( 125 + 8775 )

= 2368 x 8900

= 21075200

b) 1995 x 3692 + 3692 x 5

 = ( 1995 + 5 ) x 3692

 = 2000 x 3692

 = 7384000

c) 117 x 89 + 117

= 117 x ( 89 + 1 )

= 117 x 90

= 10530

a) 2368 x ( 125 + 8775) = 2368 x 8900 = 21075200

b) 3692 x (1995 + 5 ) =3692 x 2000 =7348000

c) 117 x ( 89 + 1 ) = 117 x 90 = 10530

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

Bài làm 

Sửa đề : \(\left(2x+3\right)-117=212\)( coppy lại đề nó vậy đấy, ko sao )

\(\Leftrightarrow2x+3=329\Leftrightarrow2x=326\Leftrightarrow x=163\)

(2x+ 3) - 117 = 212

  => 2x+ 3 = 212 + 171

       2x+ 3 = 383

          2x   = 383 - 3

          2x   = 380

            x   = 380 : 2

            x   = 190

giúp mình nha

                                  Bài giải

\(\left(2x+3\right)-117=212\)

\(2x+3=212+117\)

\(2x+3=329\)

\(2x=326\)

\(x=163\)