3 câu giúp mình với ạ

`a)`

`x^3-2x^2=0`

`<=>x^2.(x-2)=0`

`<=>` \(\left[ \begin{array}{l}x^2=0\\x-2=0\end{array} \right.\) 

`<=>` \(\left[ \begin{array}{l}x=0\\x=2\end{array} \right.\) 

Vậy `x in {0;2}`

`b)`

`5x.(14-x)+14-x=0`

`<=>5x.(14-x)+(14-x).1=0`

`<=>(5x+1).(14-x)=0`

Trường hợp `1:`

`5x+1=0`

`=>5x=-1`

`=>x=-1/5`

Trường hợp `2:`

`14-x=0`

`<=>x=14-0`

`<=>x=14`

Vậy `x in {-1/5;14}`

`e)` `x^2-x+3.(x-1)=0`

`<=>(x^2-x)+3.(x-1)=0`

`<=>x.(x-1)+3.(x-1)=0`

`<=>(x+3).(x-1)=0`

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

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

Vậy `x in {-3;1}`