Question 830241
First make the equations slope-intercept form {{{y=mx+b}}}


{{{x+y=4}}}
{{{y=-x+4}}}
This line has a slope of -1 and has a y intercept at (0,4).


{{{3x+3y=6}}}
{{{3y=-3x+6}}}
{{{y=-x+2}}}
This line has a slope of -1 and has a y intercept of (0,2).

These lines are parallel so they will never instersect.  The answer is C.
{{{graph( 300, 200, -10, 10, -10, 10, -x+4, -x+2 )}}}

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