Question

if a square + b square + c square = 250 and ab + bc + ca = 3 , find a + b + c

Answer 1

(a+b+c)² = a² + b² + c² + 2(ab+bc+ca)
(a+b+c)² = 250 + 2*3
(a+b+c)² = 256
a+b+c = √256 = 16