a: \(A=\sqrt{50}-3\sqrt8+\sqrt{\left(\sqrt2+1\right)^2}\)
\(=5\sqrt2-3\cdot2\sqrt2+\sqrt2+1=1\)
\(B=\frac{x\cdot\sqrt{x}-\sqrt{x}}{x-1}+\frac{x-1}{\sqrt{x}+1}\)
\(=\frac{\sqrt{x}\left(x-1\right)}{x-1}+\frac{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}{\sqrt{x}+1}=\sqrt{x}+\sqrt{x}-1=2\sqrt{x}-1\)
b: A<=B
=>B>=A
=>\(2\sqrt{x}-1\ge1\)
=>\(2\sqrt{x}\ge2\)
=>\(\sqrt{x}\ge1\)
=>x>=1
Kết hợp ĐKXĐ, ta được: x>1
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