SOLUTION: how do i solve 1-3x/x-4= 8/4-x

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Question 452642: how do i solve 1-3x/x-4= 8/4-x
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
how do i solve %281-3x%29%2F%28x-4%29 = 8%2F%284-x%29
Cross multiply
(1-3x)(4-x) = 8(x-4)
FOIL the left side
4 - x - 12x + 3x^2 = 8x - 32
4 - 13x + 3x^2 = 8x - 32
Combine like terms on the left
3x^2 - 8x - 13x + 4 + 32 = 0
A quadratic equation
3x^2 - 21x + 36 = 0
Factors to
(3x - 12)(x - 3) = 0
3x = 12
x = 4
and
x = 3
:
We can see that x = 4, is not a solution, it causes denominator to be 0
x = 3 is the only solution
;
:
You can check x=3 in the original equation