(x^2-5x-9)/(x-3)
Please can you explain this in very simple terms, I don't understand this please help.
2007-05-04 19:04:26 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
the answer is negative 15 in the answers but how?
2007-05-04 19:17:08 · update #1
(x^2 - 5x - 9) / (x - 3)
You start with a suspicion that (x - 3) may be a factor of (x^2 - 5x - 9).
-9 = -3(+3)
but - 3 + 3 = 0, not -5, so (x - 3) can't be a factor.
In fact, (x^2 - 5x - 9) does not have integer factors.
completing the square, you have
(x^2 - 5x + (5/2)^2 - (5/2)^2 - 9) =
(x - 5/2)^2 - 25/4 - 36/4) =
(x - 5/2)^2 - 61/4) =
(x - 5/2 - (1/2)√61)(x - 5/2 + (1/2)√61)
Dividing by (x - 3) you have
(x - 5/2 - (1/2)√61)(x - 5/2 + (1/2)√61)/(x - 3)
In my opinion, the original expression is simpler.
You can "divide it out" and reach an answer of
x - 2 - 15/(x - 3)
but this is not the most elegant of answers, either.
2007-05-04 19:21:30 · answer #1 · answered by Helmut 7 · 0⤊ 1⤋
well, first you would have to factor the polynomial on top ( the large one) but unfortunatley it doesn't factor out easily. You have to use the quadratic formula and multiply that answer by the reciprocal of (x-3)
2007-05-04 19:13:09 · answer #2 · answered by Anonymous · 0⤊ 0⤋
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2017-01-09 12:48:24 · answer #3 · answered by ? 4 · 0⤊ 0⤋
In most cases, when you factor a quadratic, you are looking for rational roots (integral is better but we'll settle for rational). You can always find the roots, but they can (as in this case) be irrational. So you can't factor this polynomial any further.
2007-05-04 19:15:47 · answer #4 · answered by cattbarf 7 · 0⤊ 1⤋
x^2 -5x -9 / x - 3
ans : Q: x - 2
R : + 3
It is simple division sum
first divide with x and then with -2
2007-05-04 19:12:16 · answer #5 · answered by Anonymous · 0⤊ 2⤋