Find the value of a + b + c when ab + bc + ca = - 4 and a² + b² + c² = 17?
Find the value of a + b + c when ab + bc + ca = - 4 and a² + b² + c² = 17?
Explanation
Given:
ab + bc + ca = -4
a² + b² + c² = 17
Using the identity (a + b + c)² = a² + b² + c² + 2(ab + bc + ca):
(a + b + c)² = 17 + 2(-4)
= 17 - 8
= 9
a + b + c = ±√9
= ±3