Examveda
Examveda

If a2 + b2 + c2 = 6.25 and (ab + bc + ca) = 0.52, what is the value of (a + b + c), if (a + b + c) < 0?

A. ±2.7

B. -2.7

C. -2.8

D. ±2.8

Answer: Option B

Solution(By Examveda Team)

a2 + b2 + c2 = 6.25
ab + bc + ca = 0.52
As we know-
(a + b + c)2 = a2 + b2 + c2 + 2(ab + bc + ca)
(a + b + c)2 = 6.25 + 2 × 0.52
(a + b + c)2 = 6.25 + 1.04
(a + b + c)2 = 7.29
a + b + c = ±2.7
Since a + b + c < 0
then, a + b + c = -2.7

This Question Belongs to Arithmetic Ability >> Algebra

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