Question

Answer 1

a: Thay x=25 vào B, ta được:

\(B=\dfrac{1}{5-2}=\dfrac{1}{3}\)

b: \(P=\dfrac{x+2-2x+4\sqrt{x}+x-1}{\left(\sqrt{x}-2\right)\cdot\left(\sqrt{x}+1\right)}\cdot\dfrac{\sqrt{x}-2}{1}\)

\(=\dfrac{4\sqrt{x}+1}{\sqrt{x}+1}\)

c: \(P^2=P+2\)

\(\Leftrightarrow\left(P-2\right)\left(P+1\right)=0\)

\(\Leftrightarrow\dfrac{4\sqrt{x}+1-2\sqrt{x}-2}{\sqrt{x}+1}\cdot\dfrac{4\sqrt{x}+1+\sqrt{x}+1}{\sqrt{x}+1}=0\)

\(\Leftrightarrow2\sqrt{x}-1=0\)

hay x=1/4