If x + y = 5 and x2 + y2 = 17 then the value of (x - y)2 is equal to:
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 9
⇒ (x + y)2 = x2 + y2 + 2xy
⇒ 2xy = 25 - 17 = 8
Then,
(x - y)2 = x2 + y2 - 2xy
= 17 - 8
= 9
∴ (x - y)2 = 9