Question

Answer 1

a) ĐKXĐ : \(x\ge0;x\ne4;x\ne1\)

b) \(A=\dfrac{\sqrt{x}-1}{\sqrt{x}-2}-\dfrac{\sqrt{x}-2}{\sqrt{x}-1}+\dfrac{\left(\sqrt{x}-2\right)^2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}-1\right)}\)

\(=\dfrac{\sqrt{x}-1}{\sqrt{x}-2}-\dfrac{\sqrt{x}-2}{\sqrt{x}-1}+\dfrac{\sqrt{x}-2}{\sqrt{x}-1}=\dfrac{\sqrt{x}-1}{\sqrt{x}-2}\)

 

Answer 2

c: Để A nguyên thì \(\sqrt{x}-2\in\left\{1;-1\right\}\)

hay \(x=9\)