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Determinati multimile A si B stiind ca: A={x € N/2x+1|15}; B={x+1 supra 2x+1/x € A}

VA ROGG
DAU COROANA SI 15 PUNCTE

Răspuns :

Cristinatibulca
2x+1∈D15
D15={1,3,5,15}
2x+1∈{1,3,5,15}
2x∈{0,2,4,14}
x∈{0,1,2,7}, A={0,1,2,7}

x=0, (x+1)/(2x+1)=1 
x=1, (x+1)/(2x+1)=2/3
x=2, (x+1)(2x+1)=3/5
x=7, (x+1)(2x+1)=8/15
B={1,2/3,3/5,8/15}