SOLUTION: show that if a subset b, then c-b subset c-a.

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Question 752657: show that if a subset b, then c-b subset c-a.
Answer by dkppathak(439) About Me  (Show Source):
You can put this solution on YOUR website!
a is sub set of b
x belongs to a and x also belongs to b
and y does not belong to a but y belong to b
to show c-b sub set of c-a
c-b
x belong c and x does not belongs b
same way
c-a
x belongs to c and x does not belongs to a
we can show
c-b is subset of c-a
x belong to c-b and x belongs to c-a
and y does not belongs to c-b but y belongs to c-a
let A ={123456} B={12345678} C={123456789}
a is sub set of b
c-a ={789}
c-b = {9}
we can say now that
c-b is subset of c-a
hence proved