If (a^2 + b^2) = 10 and ab = 3; find a + b = ?

Question

If (a² +b²) = 10 and ab = 3; find a + b = ?

A. 8

B. 4

C. 0

D. 16

Answer: B. 4

Solution:

(a + b)² = a² + b² + 2ab

⇒ (a + b)² =10 + 2 × 3

⇒ (a + b)² = 10 + 6

⇒ (a + b)² = 16

⇒ (a + b) = √16

⇒ (a + b) = 4

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