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If x # y is defined for all integers by the equation above, and if x # y is 7, what is a possible value of x?


The answers given are 14, 7, 1, 49, and 3.

If x y is defined for all integers by the equation above and if x y is 7 what is a possible value of x The answers given are 14 7 1 49 and 3 class=

Respuesta :

mhanifa

Answer:

  • A. 14

Step-by-step explanation:

Given

  • x#y = 1/(1/x + 1/y)

This is symmetrical for x and y, so

  • y#x = 1/(1/y + 1/x) is same as above

If x#y = 7, then:

  • 7 = 1/(1/x + 1/y)
  • 1/(1/7) = 1/(1/x + 1/y)
  • 1/7 = 1/x + 1/y

Possible value of x is 14, then y = 14 as well:

  • 1/7 = 1/14 + 1/14
  • 1/7 = 2/14
  • 1/7 = 1/7

Correct choice is A

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