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Why can't x-2/x-6 simplify to 1/3?
12 Answers
- Iggy RockoLv 72 months ago
1/3 =
1/3 * (x - 2)/(x - 2) =
1(x - 2)/(3(x - 2)) =
(x - 2)/(3x - 6), not (x - 2)/(x - 6)
- Jeff AaronLv 72 months ago
Is x - (2/x) - 6 the same as 1/3? It depends on the value of x.
x - (2/x) - 6 = 1/3
Multiply through by 3x:
3x^2 - 6 - 18x = x
3x^2 - 18x - 6 - x = 0
3x^2 - 19x - 6 = 0
x = (-(-19) +/- sqrt((-19)^2 - 4(3)(-6))) / (2*3)
x = (19 +/- sqrt(361 + 72)) / 6
x = (19 +/- sqrt(433)) / 6
x =~ 6.6347753411141352717951502536839 or -0.30144200778080193846181692035056
So if x is one of those two values, then yes, you can simplify like that, but otherwise, no.
Or did you mean:
(x - 2) / (x - 6) = 1/3
Cross-multiply:
3(x - 2) = x - 6
3x - 6 = x - 6
3x - 6 - x + 6 = 0
2x = 0
x = 0/2
x = 0
So if x = 0, then yes, you can simplify like that, but otherwise, no.
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- lenpol7Lv 72 months ago
Let x = 4
Hence
(4 - 2)/(4 - 6) =
2/2 = 1
This is just an example of using a non-zero number to show that (x -2)/(x -6) is no simply '1/3'.
- ?Lv 72 months ago
Assuming this is (x - 2) / (x - 6), x - 2 is one expression by itself and shares no common and cancellable factors with x - 6. However, if x = 0, the entire rational expression will equal 1/3 ((0 - 2) / (0 - 6) = -2 / -6 = 1/3).
- JimLv 72 months ago
Assuming you meant (x-2)/(x-6)
let's try one example to disprove it's 1/3:
If x = 2, then
(2-2)/(2-6) = 0, so you know for sure it's not 1/3
In fact, it's 1/3 for only where x=0, all other values it's some other value.
- llafferLv 72 months ago
(x - 2) / (x - 6)
Because x isn't a factor so you can't just divide both sides by it to cancel them out.
That's like saying:
8 / 4
and you want to cancel out a 10 (x = 10 from your example).
That doesn't work.