\(A=4x^2+12x+2020=\left(4x^2+12x+9\right)+2011=\left(2x+3\right)^2+2011\ge2011\)Dấu "=" xảy ra \(\Leftrightarrow\left(2x+3\right)^2=0\Leftrightarrow x=-\dfrac{3}{2}\)
Vậy \(MinA=2011\)
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