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Question 543527:  (Y/Y+7) + (42/Y^2-49)= 3/Y-7 
 Answer by IFY(62)      (Show Source): 
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   (Y/Y+7) + (42/Y^2-49)= 3/Y-7
 
     FIND THE L.C.M
 
   Y(Y^2 - 49) + 42 (Y +7) / (Y +7)(Y^2 - 49) = 3 / Y - 7
 
   SIMPLIFY THEM
 
   Y^3 - 49Y +42Y + 294 / Y^3 - 49Y + 7Y^2 - 343 = 3 / Y - 7
 
  
    Y^3 - 7Y + 294 / Y^3 - 7Y^2 - 49Y - 343 = 3 / Y - 7
 
         CROSS- MULTIPLY
 
 
   (Y - 7)( Y^3 - 7Y + 294) = 3( Y^3 - 7Y^2 - 49Y - 343)
 
 
    THEN MULTIPLY THEM TOGETHER
 
Y^4 -7Y^2 + 294Y - 7Y^3 + 49Y - 2058 = 3Y^3 - 21Y^2 - 147Y - 1029
 
 
    ARRANGE THEM ACCORDINGLY
 
    Y^4 - 7Y^3 - 7Y^2 + 343Y - 2058 - 3Y^3 + 21Y^2 + 147Y + 1029 = 0
 
 
   Y^4 - 10Y^3 + 14Y^2 + 490Y - 1029 = 0
 
         OR
 
  Y^4 - 10Y^3 + 14Y^2 + 490Y = 1029 
  
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