Question

x - y = 4, x² + y² =10 ആയാൽ x + y എത്ര?

• A. 2
• B. 3
• C. 4
• D. 5

Answer 1

Answer:

A. 2

(x + y)² + (x - y)² = x² + 2xy +y² + x² - 2xy + y² = 2(x² + y²) (x+ y)² = 2(x² + y²) - (x - y)² = 2 × 10 - 16 = 20 - 16 = 4 ( x + y) = 2