Question 156658
can i ask u how to show that B is a subset of V 
as V={(a,b,c)|a-b=c} and B={(0,-1,1),(1,-1,2)}
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V is the set of all triplets of the form (a,b,c) that satisfy
the condition that a-b=c.
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But (0,-1,1) is a triplet where 0-(-1)=1;
And (1,-1,2) is a triplet where 1-(-1)=2.
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Since both elements of B satisfy the conditions of V,
B is a subset of V.
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Cheers,
Stan H.