Question

daca a,b si c sunt nr naturale aatfel incat a+b=23 si b+c=31 atunci determina valuarea expresiei5*a+7*b+2*c

Answer 1

5a + 7b + 2c = 5a + 5b + 2b + 2c = 5 · ( a + b) + 2 · ( b + c) = 5 · 23 + 2 · 31 = 115 + 62 = 177