If (J + K) is 25 and (J × K) is 150, find the value of (J - K)?

  1. ±3
  2. ±6
  3. ±5
  4. ±8

Answer (Detailed Solution Below)

Option 3 : ±5
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Detailed Solution

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Given,

(J + K) = 25      ----(1)

and J × K = 150

By squaring the above equation, we get

⇒ (J + K)2 = 252

⇒ J2 + K2 + 2JK = 625

⇒ J2 + K2 = 625 - 300

⇒ J2 + K2 = 325      ----(2)

To get (J - K), we have to subtract 2JK from eq.(2)

⇒ J2 + K2 - 2JK = 325 - 2JK

⇒ (J - K)2 = 325 - 300 = 25

∴ (J - K) = ±5
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