Question

 

Answer 1

a: ĐKXĐ: \(x\notin\left\{2;-2\right\}\)

Answer 2

a) ĐKXĐ: \(x\ne\pm2\)

\(B=\dfrac{4\left(x-2\right)+2\left(x+2\right)-5x+6}{\left(x-2\right)\left(x+2\right)}=\dfrac{x+2}{\left(x-2\right)\left(x+2\right)}=\dfrac{1}{x-2}\)

b) \(B=\dfrac{1}{x-2}=\dfrac{1}{4-2}=\dfrac{1}{2}\)

c) \(B=\dfrac{1}{x-2}>0\Leftrightarrow x-2>0\Leftrightarrow x>2\)

d) \(P=B\left(x^3-4x\right)=\dfrac{1}{x-2}.x\left(x-2\right)\left(x+2\right)=x\left(x+2\right)=x^2+2x=\left(x+1\right)^2-1\ge-1\)

\(minP=-1\Leftrightarrow x=-1\)