SOLUTION: [40/(x-2)] - 1 = [42/(x+2)] Solve for x: TRIED: and got -x^2 - 2x + 168 = 0 ; but this is unfactorable... unsolveable?

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: [40/(x-2)] - 1 = [42/(x+2)] Solve for x: TRIED: and got -x^2 - 2x + 168 = 0 ; but this is unfactorable... unsolveable?      Log On


   

Question 234376: [40/(x-2)] - 1 = [42/(x+2)]
Solve for x:
TRIED: and got -x^2 - 2x + 168 = 0 ; but this is unfactorable... unsolveable?
Found 2 solutions by user_dude2008, checkley77:
Answer by user_dude2008(1862) About Me  (Show Source):
You can put this solution on YOUR website!
[40/(x-2)] - 1 = [42/(x+2)]

Multiply through by LCD (x-2)(x+2)

40(x+2)-(x-2)(x+2)=42(x-2)


40(x+2)-(x^2-4)=42(x-2)

40x+80-x^2+4=42x-84

40x+80-x^2+4-42x+84=0

-x^2-2x+168=0

x^2+2x-168=0

(x+14)(x-12)=0

x+14=0 or x-12=0

x=-14 or x=12 <--------- Answers


Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
-x^2 - 2x + 168 = 0 THIS EQUATION IS FACTORABLE
X^2+2X-168=0
(X-12)(X+14)=0
X-12=0
X=12 ANS
X+14=0
X=-14 ANS.
PROOF, IF YOU SOLVED THE EQUATION CORRECTLY FOLLOWS:
[40/(x-2)] - 1 = [42/(x+2)]
[40/(12-2)]-1=[42/(12+2)
40/10-1=42/14
4-1=3
3=3
AND:
[40/(-14-2)]-1=[42/(-14+2)
(40/-16)-1=42/-12
-2.5-1=-3.5
-3.5=-3.5