Mark each statement True or False. Justify each answer.\ (a) If

A\\\\cap B=(O)/()

, then either

A=(O)/()

or

B=(O)/()

.\ (b) If

xinA\\\\cup B

, then

xinA

or

xinB

.\ (c) If

xin(A)/(/)B

, then

xinA

or

x!inB

.\ (d) In proving

SsubeT

, one should avoid beginning with "Let

xinS

," because this assumes that

S

is nonempty.

2. Mark each statement True or False. Justify each answer. (a) If AB=, then either A= or B=. (b) If xAB, then xA or xB. (c) If xA\B, then xA or x/B. (d) In proving ST, one should avoid beginning with "Let xS," because this assumes that S is nonempty