[tex]1)(1 - \frac{1}{2} )(1 + 0.5) = (1 - \frac{1}{2} )(1 + \frac{5}{10} ) = (1 - \frac{1}{2} )(1 + \frac{1}{2} ) = {1}^{2} - {( \frac{1}{2} )}^{2} = 1 - \frac{ {1}^{2} }{ {2}^{2} } = 1 - \frac{1}{4} = \frac{4}{4} - \frac{1}{4} = \frac{4 - 1}{4} = \frac{3}{4} [/tex]
[tex]2) log_{3}(x + 5) = log_{3}(9) [/tex]
Condiția de existență :
[tex]x + 5 > 0[/tex]
[tex]x + 5 = 9 = > x = 9 - 5 = 4 > 0 \: verifica \: conditia[/tex]
