Question

din ce numar se scade sfertul lui 36 pentru a optine un numar cuprins intre 7 si 12

Answer 1

7 < x-(36:4) < 12
7 < x-9 < 12

7 < x-9 ; adaugam 9 in stanga si dreapta inegalitatii => 7+9<x-9+9
=> 16 < x

x-9 < 12; adaugam 9 in stg si dr inegalitatii => x-9+9 < 12+9
=> x< 21

=>x={17; 18; 19; 20}; x ∈ N

Answer 2

1)36÷4=9;
2)7+12=19;
3)19-9=10.