Hello,
As you write 1/x, x must be different of 0.
[tex] \dfrac{1}{x} = \dfrac{x+3}{2x^2} \\
==\textgreater\ 2x^2=x^2+3x \cross`\product \\
==\textgreater\ x^2-3x =0\\
==\textgreater\ x(x-3)=0 \\
==\textgreater\ x=0 (to exclude) or x=3\\
Answer\ x=3
[/tex]
