Question

Determinati x astfel incat:
3,(2)+x<9,(7) in N

Answer 1

$3,(2)+x\ \textless \ 9,(7) \\ \frac{29}{9} +x\ \textless \ \frac{88}{9} \\ x\ \textless \ \frac{88}{9} - \frac{29}{9} \\ x\ \textless \ \frac{59}{9} \\ x\ \textless \ 6,(5)$

Answer 2

3,[2]<x<9,[7]⇒x∈N;
⇒3,[2]=29/9;
⇒9,[7]=88/9;
⇒29/9<x<88/9
⇒29/9<9x/9<88/9;
⇒29<9x<88⇒9x∈[36,45,54,63,72,81]⇒6 valori;
⇒x=[4,5,6,7,8,9]⇒6 variante;