Question 850826
There are an infinite number of non-negative solutions.
{{{3x+7y=999}}}
{{{7y=999-3x}}}
{{{y=(999-3x)/7}}}
For {{{y>=0}}},
{{{(999-3x)/7>=0}}}
{{{999-3x>=0}}}
{{{-3x>=-999}}}
{{{0<=x<=333}}}