Să se calculeze
a) [tex] \frac{2}{x+2} + \frac{1}{x+3} [/tex]

b) [tex] \frac{x+2}{x+3} * \frac{x+3}{x+4} [/tex]

c) [tex] \frac{x-3}{x-4} / \frac{x-3}{x-5} [/tex]