Question 941314
By definition, an odd function is defined as 
{{{f(-x)=-f(x)}}}
So then if g(x) is defined as {{{-f(x)}}} when {{{x<0}}}, then
{{{g(x)=-(-f(x))}}} when {{{x<0}}} or
{{{g(x)=f(x)}}} 
which is the definition of an even function.