a+b=27 b+c=7 calculati 3a+5b+2c ,cu metoda factorului comun

Răspuns :

a+b=27 /×3 => 3a+3b=81
b+c=7 /×2 => 2b+2c=14

3a+3b+2b+2c=81+14
3a+5b+2c=95
coroana?

3a+5b+2c=3a+3b+2b+2c=3(a+b)+2(b+c)=3x27+2x7=81+14=95