`y10000`
`a )`
$\sqrt{4x²+9x+12x}$ - 2 = 0
`<=>\sqrt{4x²+12x+9}= 2`
`<=> \sqrt{(2x+3)²}=2`
`<=>|2x + 3|=2`
`<=>` \(\left[ \begin{array}{l}2x+3=2\\2x+3=-2\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}x=\frac{-1}{2}\\x=\frac{-5}{2}\end{array} \right.\)
$\text{Vậy x =...}$