Question

pf me ajude 
determine a soma e o protudo de:
5+ raiz de 2  e    5- raiz de 2
    2                           2

Answer 1

$(a + b)(a - b) = a^{2} - b^{2}$
_____________________

$\frac{5 + \sqrt{2} }{2} + \frac{5 - \sqrt{2}}{2} = \frac{5 + \sqrt{2} + 5 - \sqrt{2}}{2} = \frac{10}{2} = 5$

$(\frac{5 + \sqrt{2} }{2}) * (\frac{5 - \sqrt{2}}{2}) = \frac{(5 + \sqrt{2})(5 - \sqrt{2})}{4} = \frac{5^{2} - \sqrt{2}^{2} }{4} = \frac{25 - 2}{4} = \frac{23}{4}$