\[\frac{x^{2}}{x^{2} + 2x + 1} - \frac{x - 1}{x + 1} =\]
\[= \frac{x^{2}}{(x + 1)^{2}} - \frac{x - 1}{x + 1} =\]
\[= \frac{x^{2} - (x - 1)(x + 1)}{(x + 1)^{2}} =\]
\[= \frac{1}{(19 + 1)^{2}} = \frac{1}{20^{2}} =\]
\[= \frac{1}{400} = 0,0025\]