Question

if a²+b²+c²=250,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 = square root of 256
a+b+c = 16 Answer.