15:
a: \(Q=\dfrac{x+\sqrt{x}+1}{x+1}:\dfrac{x+1-2\sqrt{x}}{\left(x+1\right)\left(\sqrt{x}-1\right)}\)
\(=\dfrac{x+\sqrt{x}+1}{x+1}\cdot\dfrac{\left(x+1\right)}{\sqrt{x}-1}=\dfrac{x+\sqrt{x}+1}{\sqrt{x}-1}\)
b: Q>1
=>Q-1>0
=>\(\dfrac{x+\sqrt{x}+1-\sqrt{x}+1}{\sqrt{x}-1}>0\)
=>căn x-1>0
=>x>1