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Dragos35
a fost răspuns

A={X∈N I(10-x)(2x-3)=21}      B={X∈N I33:X}      AUB     A∧B  (A\B)∧(B\A)

Răspuns :

(10-x)(2x-3)=21
20x-30-2x²+3x-21=0
-2x²+23x-51=0       (-1)
2x²-23x+51=0
Δ=b²-4ac=529-408=121
x1=(23-11)/4=3
x2=(23+11)/4=34/4=17/2
A={3}
B={1,3,11,33}
AUB={1,3,11,33}
A∧B ={3}
(A\B)∧(B\A)={3}∧{1,11,33}=Ф

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