Question 856883
P:  {{{x=(0-2)/2=-1}}}; {{{y=(1+3)/2=2}}}
P is (-1,2)
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Q:  {{{x=(0+2)/2=1}}}; {{{y=(1-1)/2=0}}}
Q is (1,0)
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Slope of BC, {{{(3-(-1))/(-2-2)=4/(-4)=-1}}}.
Slope of PQ, {{{(2-0)/(-1-1)=2/(-2)=-1}}}.
Slopes of BC and PQ are both -1, equal, so BC and PQ are parallel.