\"\"

\

Multiply nominator and denominator by [√(x2+3x+1)+x].

\

\"\"

\

Mathematics formula: (a+b)(a-b) = (a2-b2).

\

\"\"

\

\"\"

\

\"\"

\

\"\"

\

\"\"

\

\"\"

\

\"\"

\

\"\"

\

\"\"