Question

Answer 1

1: \(P=\dfrac{2\sqrt{x}\left(\sqrt{x}-3\right)+\left(\sqrt{x}+1\right)\left(\sqrt{x}+3\right)-7\sqrt{x}-3}{x-9}\)

\(=\dfrac{2x-6\sqrt{x}+x+4\sqrt{x}+3-7\sqrt{x}-3}{x-9}\)

\(=\dfrac{3x-9\sqrt{x}}{x-9}=\dfrac{3\sqrt{x}}{\sqrt{x}+3}\)

2: P<1

=>\(\dfrac{3\sqrt{x}-\sqrt{x}-3}{\sqrt{x}+3}< 0\)

=>2căn x-3<0

=>0<=x<9/4

3: P nguyên

=>3căn x chia hết cho căn x+3

=>3căn x+9-9 chia hết cho căn x+3

=>căn x+3 thuộc {3;9}

=>x thuộc {0;36}