Question

giup minh cau nay voi

Answer 1

a: \(=\dfrac{x+1}{\sqrt{x}\left(\sqrt{x}-1\right)}:\dfrac{\sqrt{x}-1+2}{x-1}\)

\(=\dfrac{x+1}{\sqrt{x}\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\cdot\left(x-1\right)=\dfrac{x+1}{\sqrt{x}}\)

b: A=2

=>x+1=2 căn x

=>x=1(loại)

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

\(=x-4\sqrt{x}+4-3=\left(\sqrt{x}-2\right)^2-3>=-3\)

Dấu = xảy ra khi x=4