Question

am o problema de rezolvat la matematica.

determinati numerele naturale a,b,c stiind ca :

a) a+b=90 b+c=21 a+c=75;
b) a+b=70 b+c=11 a+c=65

Answer 1

a)Adunand cele trei egaliati obtinem:
a+b+b+c+a+c=90+21+75
2a+2b+2c=186
2(a+b+c)=186
a+b+c=186:2
a+b+c=93
cum a+b=90 inlocuim si-l aflam pe c
90+c=93⇒c=93-90=3
a+21=93⇒a=93-21=72
b+3=21⇒b=21-3=18
b)a+b+b+c+a+c=70+11+65
2a+2b+2c=146
2(a+b+c)=146
a+b+c=146:2
a+b+c=73
70+c=73⇒c=73-70=3
b+3=11⇒b=11-3=8
a+3=65⇒a=65-3=62