Question

Answer 1

a: \(P=\dfrac{3x-6+2x+4-x^2-4}{\left(x-2\right)\left(x+2\right)}\cdot\dfrac{\left(x+2\right)^2}{1}\)
\(=\dfrac{-x^2+5x-6}{\left(x-2\right)}\cdot\dfrac{x+2}{1}=\dfrac{-\left(x-2\right)\left(x-3\right)}{\left(x-2\right)}\cdot\left(x+2\right)=-\left(x-3\right)\left(x+2\right)\)

b: \(P=-\left(x^2-x-6\right)\)

\(=-\left(x^2-x+\dfrac{1}{4}-\dfrac{25}{4}\right)\)

\(=-\left(x-\dfrac{1}{2}\right)^2+\dfrac{25}{4}< =\dfrac{25}{4}\)

Dấu = xảy ra khi x=1/2