x = 4

\(x+\left|-3\right|=-\left|-7\right|\)

\(x+3=-7\)

\(x=-7-3\)

\(x=-10\)

x^3+1=9

x^3=8

x^3=2^3

=>x=2

=>x³=8

hay x=2

`x^3+1=9`

`x^3=8`

`x^3=2^3`

`=>x=2`

\(x-\dfrac{1}{4}=\dfrac{-21}{10}\)

\(x=\dfrac{-21}{10}+\dfrac{1}{4}\)

\(x=\dfrac{-42}{20}+\dfrac{5}{20}=\dfrac{-37}{20}\)

\(\Leftrightarrow x^3+2x^2-3x-x^3-3x^2=-4\)

\(\Leftrightarrow x^2+3x-4=0\)

=>(x+4)(x-1)=0

=>x=-4 hoặc x=1

\(x^3-5x^2-9x+45=0\)

=>\(x^2\left(x-5\right)-9\left(x-5\right)=0\)

=>\(\left(x-5\right)\left(x^2-9\right)=0\)

=>\(\left(x-5\right)\left(x-3\right)\left(x+3\right)=0\)

=>\(\left[{}\begin{matrix}x-5=0\\x-3=0\\x+3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=3\\x=-3\end{matrix}\right.\)

`x^3 -5x^2 -9x+45=0`

`<=> (x^3 -5x^2 )-(9x-45)=0`

`<=> x^2 (x-5)- 9(x-5)=0`

`<=>(x-5)(x^2 -9)=0`

`<=>(x-5)(x-3)(x+3)=0`

\(\Leftrightarrow\left[{}\begin{matrix}x-5=0\\x-3=0\\x+3=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=5\\x=3\\x=-3\end{matrix}\right.\)

`x-1/8=1/4xx2/3`

`x-1/8=1/6`

`x=1/6+1/8`

`x=7/24`

x - 1/8 = 1/6

x         = 6/48 + 8/48
x         = 14/48

x - 1/8 = 1/4 x 2/3

x - 1/8=   1/6

x        = 1/6 + 1/8

x       =  14/48

x = 4/5 : 3/4

x = 16/15

x = 5/9 : 8/3

x = 5/9 x 3/8

x = 5/24

\(x=\dfrac{4}{5}\times\dfrac{4}{3}\)

\(x=\dfrac{16}{15}\)

-----------------------

\(x=\dfrac{5}{9}\times\dfrac{3}{8}\)

\(x=\dfrac{5}{24}\)

\(x\times\dfrac{3}{4}=\dfrac{4}{5}\)

\(x=\dfrac{4}{5}:\dfrac{3}{4}\)

\(x=\dfrac{4}{5}\times\dfrac{4}{3}\)

\(x=\dfrac{16}{15}\)

\(\dfrac{5}{9}:x=\dfrac{8}{3}\)

      \(x=\dfrac{5}{9}:\dfrac{8}{3}\)

      \(x=\dfrac{5}{9}\times\dfrac{3}{8}\)

     \(x=\dfrac{15}{72}\)

    \(x=\dfrac{5}{24}\)

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

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

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

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