Respostas

2014-07-06T17:15:24-03:00
Para ser nula... g(x) deve ser igual a zero.

g(x)= \frac{2}{5}x- \frac{6}{7}  \\\\\\g(x)=0\\\\ \frac{2}{5}x- \frac{6}{7}  =0\\\\ \frac{2}{5}x= \frac{6}{7} \\\\x= \frac{ \frac{6}{7} }{ \frac{2}{5} } \\\\x= \frac{6}{7}* \frac{5}{2}\\\\x= \frac{30}{14}  ~~:(2)\\\\\boxed{x= \frac{15}{7} }