Răspuns:
Explicație pas cu pas:
a+b+c=90
a/2-5=n ⇔ (a-10)/2=n ⇔ a-10=2n ⇔ a=2n+10
b/2-6=n+1 ⇔ (b-12)/2=n+1 ⇔ b-12=2n+2 ⇔ b=2n+14
c/2-7=n+2 ⇔ (c-14)/2=n+2 ⇔ c-14=2n+4 ⇔ c=2n+18
Inlocuim valorile obtinute pentru a, b si c in prima relatie.
a+b+c=90 ⇔ 2n+10+2n+14+2n+18=90 ⇔ 6n+42=90 ⇔ 6n=90-42 ⇔ 6n=48 ⇔ n=48:6 ⇔ n=8
a=2n+10=2·8+10=26 a=26
b=2n+14=2·8+14=30 b=30
c=2n+18=2·8+18=34 c=34
Verificare: a+b+c=26+30+34=90
