9. abc+1816=abc7
c+6=7 => c=1
ab1+1816=ab17
b+1=1 => b=0
a01+1816=a017
a+8=10 => a=2
201+1816=2017
=> numarul cautat la inceput este 2017
Verificare:
2017 --> taiem ultima cifra --> 201
2017-201=1816
10. Fie a si b cele 2 numere
a=5b
3a*(b-750)=a*b
3(5b)*(b-750)=5b*b
15b*(b-750)=5b^2
15b^2-11250b=5b^2
11250b=10b^2 / impartim cu b
11250=10b
b=1125
a=5*1125=5625
Verificare:
1125*5625=6328125
Triplam primul numar:
3*5625=16875
Micsoram al doilea cu 750:
1125-750=375
16875*375=6328125 corect :)
