SOLUTION: (Y/Y+7) + (42/Y^2-49)= 3/Y-7

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: (Y/Y+7) + (42/Y^2-49)= 3/Y-7      Log On


   

Question 543527: (Y/Y+7) + (42/Y^2-49)= 3/Y-7
Answer by IFY(62) About Me  (Show Source):
You can put this solution on YOUR website!

(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