[tex]( \frac{1}{x} + \frac{1}{x + 1} ) \times \frac{x {}^{2} }{2x + 1} [/tex]
[tex] \frac{x + 1 + x}{x \times (x + 1)} \times \frac{x {}^{2} }{2x + 1} [/tex]
[tex] \frac{2x + 1}{x + 1} \times \frac{x {}^{2} }{2x + 1} [/tex]
[tex] \frac{1}{x + 1} \times x[/tex]
[tex]x = \frac{x}{x + 1} [/tex]
