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Given Real Valued Function, Find the Value 2 (Posted on 2023-10-09) Difficulty: 3 of 5
Consider three real numbers x, y, and z that satisfy this system of equations:
  • x+y+z=5
  • 1/(x+y) + 1/(y+z) +1/(z+x) =4/5
Find the value of x/(y+z) + y/(z+x)+ z/(x+y).

See The Solution Submitted by K Sengupta    
Rating: 5.0000 (1 votes)

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Solution No Subject | Comment 2 of 3 |
Start with the Unknown to be found, call it U:

x/(y+z) + y/(z+x)+ z/(x+y) = U
x/(5-x) + y/(5-y)+ z/(5-z) = U

1/(5-x) + 1/(5-y) + 1/(5-z) = 4/5

(x + y + z)*(1/(5-x) + 1/(5-y) + 1/(5-z)) = 4

x/(5-x) + y/(5-y)+ z/(5-z) + (y+z)/(5-x) + (x+z)/(5-y)+ (x+y)/(5-z) = 4
U + (y+z)/(5-x) + (x+z)/(5-y)+ (x+y)/(5-z) = 4
U + (y+z)/(y+z) + (x+z)/(x+z)+ (x+y)/(x+y) = 4
U + 3 = 4
U = 1

  Posted by Larry on 2023-10-09 09:35:13
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