If $ a^2 + b^2 + c^2 = 576$ and (ab + bc + ca) = 50, then what is the value of (a + b + c), if ( a + b + c) < 0 ?
Answer & explanation
Correct answer: option 3
Given,
a2 + b2 + c2 = 576
(ab + bc + ca) = 50
We know that,
(a + b + c)2 = a2 + b2 + c2 + 2(ab + bc + ca)
= (a + b + c)2 = 576 + 2 × 50 = 676
= (a + b + c) = ±26
But, it is given that (a + b + c) < 0
So, (a + b + c) = -26