\(a.ChoA\left(x\right)=0\\ tađược:-4x-5=0\\ \Leftrightarrow-4x=5\\ \Leftrightarrow x=\dfrac{-4}{5}\)
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\(b.ChoB\left(x\right)=0\\ tađược:\\\left[{}\begin{matrix}3\left(2x-1\right)=0\Rightarrow x=\dfrac{1}{2}\\\\-2\left(x+1\right)=0\Rightarrow x=-1\end{matrix}\right.\)
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\(c.ChoC\left(x\right)=0\\ tađược:\\ \left[{}\begin{matrix}2x^2-8=0\Rightarrow x=2\\\\-x^2-8=0\Rightarrow x=\sqrt{8}\end{matrix}\right.\)
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