I am currently reading vellemans how to prove it for the purpose of being able to construct a proof on my own. I would like to carry on this knowledge to also help me out with spivaks calculus So the problem is:(adsbygoogle = window.adsbygoogle || []).push({});

Prove that if a and b\c are disjoint, then a[itex]\bigcap[/itex]b[itex]\subseteq[/itex]c.

1.goal: a[itex]\bigcap[/itex]b\c=∅ → a[itex]\bigcap[/itex]b[itex]\subseteq[/itex]c

2. Givens:a[itex]\bigcap[/itex]b\c=∅ Goal:a[itex]\bigcap[/itex]b[itex]\subseteq[/itex]c

3.Givens:a[itex]\bigcap[/itex]b\c=∅ x[itex]\in[/itex]a x[itex]\in[/itex]b Goal: x[itex]\in[/itex]c

This is as far as I got. I haveE no idea where to go from here and I feel the solution is starting right at me. I think it might have something to do with the fact that a and b\c are disjoints. This might be in the wrong section but I don't no where else to put it

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# How to prove it 3.3 exercise help please

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