Question

a² + b² + c² = 42, ab + bc + ac = 29 ∴ a + b + c = ______.

विकल्प

• 16

• 14

• 12

• 10

Answer 1

a² + b² + c² = 42, ab + bc + ac = 29 ∴ a + b + c = 10.

Explanation:

(a + b + c)² = a² + b² + c² + 2(ab + bc + ac)

(a + b + c)² = 42 + 2(29)

(a + b + c)² = 42 + 58

(a + b + c)² = 100

∴ a + b + c = `sqrt100`

∴ a + b + c = 10