a) \(A=\sqrt{\dfrac{\left(x^2-3\right)^2+12x^2}{x^2}}+\sqrt{\left(x+2\right)^2-8x}\)
\(=\sqrt{\dfrac{x^4-6x^2+9+12x^2}{x^2}}+\sqrt{x^2+4x+4-8x}\)
\(=\sqrt{\dfrac{x^4+6x^2+9}{x^2}}+\sqrt{x^2-4x+4}\)
\(=\dfrac{\sqrt{x^4+6x^2+9}}{x}+\sqrt{\left(x-2\right)^2}\)
\(=\dfrac{\sqrt{\left(x^2+3\right)^2}}{x}+x-2\)
\(=\dfrac{x^2+3}{x}+x-2\)
\(=\dfrac{x^2+3+x^2-2x}{x}\)
\(=\dfrac{2x^2+3-2x}{x}\)
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