Question

Daca a+b+c=314 , calculeaza:
a) (a+b)+(b+c)+(c+a);
b) (a-b)+(b-c)-a+c.

Answer 1

a+b+c =314
a)(a+b)+(b+c)+(c+a) = a+b+b+c+c+a = 2a+2b+2c = 2 x (a+b+c) = 2 x314 = 628
b) (a-b)+(b-c)-a+c = a-b+b-c-a+c = 0