2.
|x-3|<5 ⇔ -5<x-3<5 ⇔ -2<x<8 ⇔ x∈(-2,8) ⇒ A=(-2,8)
|x|≤3 ⇔ -3≤x≤3 ⇔ x∈[-3,3] ⇒ B={-3,-2,-1,0,1,2,3}
A∩B={-1,0,1,2,3}
3.
0,(2)=2/9
2,3(6)=[tex]2 \frac{36-3}{90} =2 \frac{33}{90}=2 \frac{11}{30} = \frac{71}{30} [/tex]
Fie x- numarul rational
[tex] 3*(\frac{x}{2} - \frac{2}{9})= \frac{71}{30}
[/tex]
[tex]3*( \frac{9x-4}{18} )= \frac{71}{30} [/tex]
[tex] \frac{9x-4}{6}= \frac{71}{30} [/tex]
[tex] \frac{15(9x-4)}{90}= \frac{3*71}{90} |:90 [/tex]
135x-60=213⇔135x=273⇔x=273/135=91/45
