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Determinati multimea A intersectat cu B unde:
A={x apartine lui Z*| 5x+19 supra 2x+1 apartine lui Z}
B={x apartine lui Z | 7x+10 supra 2x-1 apartine lui Z}


Răspuns :

2x+1/5x+19  /*2⇒ 2x+1/10x+38
2x+1/2x+1   /*5⇒  2x+1/10x+5 /- ⇒2x+1/33⇒ 2x+1∈ {1,11,33,-1,-11,-33}⇒
2x∈{0,10,32,-2,-12,-34}⇒ x∈{0,5,16,-1,-6,-17} ⇒ A={5,16,-1,-6,-17}

2x-1/7x+10  /*2⇒ 2x-1/14x+20
2x-1/2x-1     /*7⇒ 2x-1/14x-7  /- ⇒2x-1/27⇒ 2x-1∈ {1,3,9,27,-1,-3,-9,-27}⇒
2x∈{2,4,10,28,0,-2,-8,-26}⇒ x∈{1,2,5,14,0,-1,-4,-13} ⇒ B={1,2,5,14,0,-1,-4,-13}

A intersectat B={-1, 5}