If 5x + 3y = 15 and 2xy = 6 then the value of 5x - 3y is:
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 3√ 5.
Given that
If 5x + 3y = 15 and 2xy = 6
As we know
⇒ (5x - 3y)2 = (5x + 3y)2 - 60xy
⇒ (5x - 3y)2 = (15)2 - 30 × 2xy
⇒ (5x - 3y)2 = 225 - 30 × 6
⇒ (5x - 3y)2 = 225 - 180
⇒ (5x - 3y)2 = 45
⇒ 5x - 3y = √45 = 3√ 5