Question 146448
{{{ graph( 300, 300, -5, 5, -10, 10, (1/3)(x-21), (1/3)(x+7)) }}}
Inconsistent system, no solution. 
Divide eq. 1.by 2, you get,
{{{x-3y=21}}}
Divide eq. 2 by 3, you get,
{{{x-3y=-7}}}
That leads to the statement
{{{21=-7}}}