Question

Answer 1

a: \(P=\frac{\sqrt{x}}{\sqrt{x}+5}+\frac{2\sqrt{x}}{\sqrt{x}-5}-\frac{3x+25}{x-25}\)

\(=\frac{\sqrt{x}\left(\sqrt{x}-5\right)+2\sqrt{x}\left(\sqrt{x}+5\right)-3x-25}{\left(\sqrt{x}+5\right)\left(\sqrt{x}-5\right)}\)

\(=\frac{x-5\sqrt{x}+2x+10\sqrt{x}-3x-25}{\left(\sqrt{x}-5\right)\left(\sqrt{x}+5\right)}=\frac{5\sqrt{x}-25}{\left(\sqrt{x}-5\right)\left(\sqrt{x}+5\right)}\)

\(=\frac{5\left(\sqrt{x}-5\right)}{\left(\sqrt{x}-5\right)\left(\sqrt{x}+5\right)}=\frac{5}{\sqrt{x}+5}\)

b: \(P=\frac57\)

=>\(\frac{5}{\sqrt{x}+5}=\frac57\)

=>\(\sqrt{x}+5=7\)

=>\(\sqrt{x}=2\)

=>x=4(nhận)