Giup em vs ạ em buồn ngủ lắm rồi

`a)` `(-12) . x = (-15) . (-4) - 2 . (x+5)`

`<=> -12x = 60 - 2x - 10`

`<=> -12x + 2x = 60 - 10`

`<=> -10x = 50`

`<=> x=50: (-10)`

`<=> x=-5`

Vậy `x=-5`

`b)` `(-5) . x + 5 = (-3) . (-8) + 14x`

`<=> -5x + 5 = 24 + 14x`

`<=> -5x - 14x = 24 - 5`

`<=> -19x = 19`

`<=> x= 19 : (-19)`

`<=>x=-1`

Vậy `x=-1`

`c)` `x^2 - 4x=0`

`<=> x(x - 4)=0`

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

`<=>` \(\left[ \begin{array}{l}x=0\\x=4\end{array} \right.\) 

Vậy `x in {0;4}`

`#vu0000`