Question

1)Numarul numerelor naturale de forma $\frac{}{a2b}$ este egal cu ....
2)Se stie ca a+b+c=7.Calculati
a)2a+2b+2c
b)10a+10b+10c
c)a·13+b·13+c·13+21

Answer 1

1) a=1,2,3,4,5,6,7,8,9
    b=0,1,2,3,4,5,6,7,8,9 deci avem 9x10=90 de numere
2)a+b+c=7
2a+2b+2c=2x7
2a+2b+2c=14
b) 10a+10b+10c= 10x7
     10a+10b+10c=70
c)vei transforma a+b+c in 7 si rezulta 13x7+21=112