Question

exercitiul 7 va rog ...

Answer 1

Răspuns:

-3<x+5<= 3 /-5 (scad pe 5 in toti membri)

-3-5<x+5-5<=3-5

-8<x<=-2 => A={-7;-6;-5;-4;-3;-2}

-6<=x<-2 =>B={-6;-5,-4;-3}

a)-5€A este adevarat

b)este fals

c)multimea vida este inclusa in toate mulțimiile ,este adevarat

d)fals

Answer 2

A={x€Z|-3<x+5<3}

B={x€Z|-6<x<2}

-3<x+5<3 /-5 => -8<x<-2 => A={-7,-6,-5,-4,-3,-2}

-6<x<2 => B={-6,-5,-4,-3,-2,-1,0,1}

a)

-5 € A - Adevarat

-5 € {-7,-6,-5,-4,-3,-2}

b)

A C B - Fals

A n B = {-6,-5,-4,-3,-2} = A/{-7}

c)

multimea vidă C B - Adevarat

B = {-6,-5,-4,-3,-2,-1,0,1}

Multimea vida este inclusa in toate multimile

d)

{-1,0,1} C A - Fals

A = {-7,-6,-5,-4,-3,-2}

{-1,0,1} n A = multimea vidă