=>x(x^2-9/16)=0

=>x(x-3/4)(x+3/4)=0

=>x=0; x=3/4; x=-3/4

72 ÷ { 16 - [ 47 + ( x - 2 ) ] } = 9

16 - [ 47 + ( x - 2 ) ] = 72 ÷ 9

16 - [ 47 + ( x - 2 ) ] = 8

47 + ( x - 2 ) = 16 - 8

47 + ( x - 2 ) = 8

x - 2 = 8 - 47

x - 2 = -39

x = -39 + 2

x = -37

Vậy x = -37

Tìm x :

a) 72: { 16 - [ 47 +( x - 2 ) ] } =9

          { 16 - [ 47 +( x - 2 ) ] }=72:9

                    [ 47 +( x - 2 ) ]=16-8

                                 x - 2 =8-47

                                       x=-39+2

                                       x=-37

nhanh len mik dag can gap

Mk lm tắt bn cố hiểu nhé

72 : { 16 - [ 47 + ( x - 2 ) ] } = 9

➡️72 : { 16 - 45 - x } = 9

➡️72 : ( - 29 - x ) = 9

➡️- 29 - x = 8

➡️- x = 37

Vậy x = - 37

Hok tốt nhé !

Ta có : 

\(\frac{x-2}{12}+\frac{x-2}{20}+\frac{x-2}{30}+\frac{x-2}{42}+\frac{x-2}{56}+\frac{x-2}{72}=\frac{16}{9}\)

\(\Leftrightarrow\)\(\left(x-2\right)\left(\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+\frac{1}{56}+\frac{1}{72}\right)=\frac{16}{9}\)

\(\Leftrightarrow\)\(\left(x-2\right)\left(\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}+\frac{1}{7.8}+\frac{1}{8.9}\right)=\frac{16}{9}\)

\(\Leftrightarrow\)\(\left(x-2\right)\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}\right)=\frac{16}{9}\)

\(\Leftrightarrow\)\(\left(x-2\right)\left(\frac{1}{3}-\frac{1}{9}\right)=\frac{16}{9}\)

\(\Leftrightarrow\)\(\left(x-2\right).\frac{2}{9}=\frac{16}{9}\)

\(\Leftrightarrow\)\(x-2=\frac{16}{9}:\frac{2}{9}\)

\(\Leftrightarrow\)\(x-2=\frac{16}{9}.\frac{9}{2}\)

\(\Leftrightarrow\)\(x-2=\frac{8}{1}.\frac{1}{1}\)

\(\Leftrightarrow\)\(x-2=8\)

\(\Leftrightarrow\)\(x=8+2\)

\(\Leftrightarrow\)\(x=10\)

Vậy \(x=10\)

Chúc bạn học tốt ~ 

(x+x+x+x+x+x)-(2/12+2/20+2/30+2/42+2/56+2/72)=16/9
6x-4/9=16/9
6x=20/9=>x=20/7

= =8/5

Ta có: \(-\frac{72}{45}=\frac{-72:9}{45:9}=\frac{-8}{5}\)

\(x+x.\dfrac{1}{3}+3y=\dfrac{1}{5}\)

\(x.\dfrac{4}{3}+3y=\dfrac{1}{5}\)

\(x.\dfrac{4}{3}=\dfrac{1}{5}-3y\)

\(x=\left(\dfrac{1}{5}-3y\right):\dfrac{4}{3}=\dfrac{3}{20}-\dfrac{9y}{4}\)

bài này không phức tạp đâu ạ ?