P = \(\left(\dfrac{\sqrt{x}+\sqrt{x}+2}{\left(\sqrt{x}+2\right)\left(\sqrt{x}-2\right)}\right).\dfrac{\sqrt{x}-2}{2}\)
   = \(\dfrac{2\left(\sqrt{x}+1\right)\left(\sqrt{x}-2\right)}{2\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}\)
   = \(\dfrac{\sqrt{x}+1}{\sqrt{x}+2}\)

P= \(\dfrac{2\sqrt{x}.\left(\sqrt{x}-3\right)+\left(\sqrt{x}+1\right).\left(\sqrt{x}+3\right)+11\sqrt{x}-3}{\left(\sqrt{x}-3\right).\left(\sqrt{x}+3\right)}\)
  = \(\dfrac{2x-6\sqrt{x}+x+3\sqrt{x}+\sqrt{x}+3+11\sqrt{x}-3}{\left(\sqrt{x}-3\right).\left(\sqrt{x}+3\right)}\)
  = \(\dfrac{3x-9\sqrt{x}}{\left(\sqrt{x}-3\right).\left(\sqrt{x}+3\right)}\)
  = \(\dfrac{3\sqrt{x}\left(\sqrt{x}-3\right)}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}\)
  = \(\dfrac{3\sqrt{x}}{\sqrt{x}+3}\)

2-4-6-8-10-12-14-16-18-20

P= \(\left(\dfrac{\sqrt{x}\left(\sqrt{x}-2\right)+2\left(\sqrt{x}+2\right)}{\left(\sqrt{x}+2\right)\left(\sqrt{x}-2\right)}\right).\dfrac{\sqrt{x}+2}{x+4}\)
  =  \(\left(\dfrac{x-2\sqrt{x}+2\sqrt{x}+4}{x-4}\right).\dfrac{\sqrt{x}+2}{x+4}\)
  =   \(\dfrac{\left(x+4\right)\left(\sqrt{x}+2\right)}{\left(\sqrt{x}+2\right)\left(\sqrt{x}-2\right)\left(x+4\right)}\)
  =\(\dfrac{1}{\sqrt{x}-2}\)  (với x > 0 và x ≠ 4)

Q= \(\left(\dfrac{a}{\sqrt{a}.\left(\sqrt{a}-2\right)}+\dfrac{a.\sqrt{a}}{\sqrt{a}.\left(\sqrt{a}-2\right)}\right)\): \(\left(\dfrac{\sqrt{a}+1}{\left(\sqrt{a}-2\right)^2}\right)\)
   =  \(\left(\dfrac{a+a\sqrt{a}}{\sqrt{a}.\left(\sqrt{a}-2\right)}\right)\). \(\left(\dfrac{\left(\sqrt{a}-2\right)^2}{\sqrt{a}+1}\right)\)
   = \(\dfrac{a.\left(\sqrt{a}+1\right).\left(\sqrt{a-2}\right)^2}{\sqrt{a}\left(\sqrt{a}-2\right).\left(\sqrt{a}+1\right)}\)
   = \(a-2\sqrt{a}\)      (với a > 0 và a ≠ 4)

0,737

số ban đầu là 0,737

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