Giúp mình vs ạ gấp lắm😢

`a) x + 15 = 0 `

`<=> x = 0 - 15 `

`<=> x = - 15 `

Vậy ` S = { - 15 } `

`b ) ( 2x + 1 ) ( 3x - 6 ) = 0 `

`<=>`\(\left[ \begin{array}{l}2x+1=0\\3x-6=0\end{array} \right.\) 

`<=>`\(\left[ \begin{array}{l}x=- \dfrac{1}{2} \\x=2\end{array} \right.\)

Vậy ` S = { - 1/2 ; 2 } `

`c) ( x - 2 )/( x + 1 ) - x/( x + 2 ) = ( x + 6 )/( x^2 + 3x + 2 ) `

`đkxđ : x \ne - 1 ; x \ne - 2 `

`<=> (( x - 2 ) ( x + 2 ))/(( x + 1 ) ( x + 2 )) - ( x ( x + 1 ))/(( x + 1 ) ( x + 2 )) = ( x + 6 )/(( x + 1 ) ( x + 2 )) `

`=> ( x^2 - 4 ) -  x ( x + 1 ) = x + 6 `

`<=> x^2 - 4 - x^2 - x = x + 6 `

`<=> - x - 4 = x + 6 `

`<=> - x - x = 6 + 4 `

`<=> - 2x = 10 `

`<=> x = - 5 ( tm )`

Vậy ` S = { - 5 } `