Tìm x biết: ( 5-3x)^7 = ( 5 -3x)^3

Đáp án + Giải thích các bước giải:

`(5-3x)^7 = ( 5 -3x)^3`

`=>(5-3x)^7 - ( 5 -3x)^3=0`

`=>(5-3x)^3 .[(5-3x)^4-1]=0`

`=>`\(\left[ \begin{array}{l}(5-3x)^3=0\\(5-3x)^4-1=0\end{array} \right.\) 

`=>`\(\left[ \begin{array}{l}5-3x=0\\(5-3x)^4=1\end{array} \right.\) 

`=>`\(\left[ \begin{array}{l}3x=5\\5-3x=1\\5-3x=-1\end{array} \right.\) 

`=>`\(\left[ \begin{array}{l}x=\dfrac{5}{3}\\3x=4\\3x=6\end{array} \right.\) 

`=>`\(\left[ \begin{array}{l}x=\dfrac{5}{3}\\x=\dfrac{4}{3}\\x=2\end{array} \right.\) 

Vậy `x in {5/3;4/3;2}`