Question

Determinati elementele multimii A={ x€ N / 7/12 mai mic x-1/15 mai mic 17/20}

Answer 1

(x-1)/15<17/20
20(x-1)<17·15
20x-20<255
20x<255+20
20x<275
x<275/20
x<13,75

7/12<(x-1)/15
7·15<12(x-1)
105<12x-12
-12x<-12-105
-12x<-117    inmultim -1
12x>117
x>117/12
x<>9,75
A={10,11,12,13}