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#1 2009-07-05 18:12:02
- Shwvvn
- Member
- Registered: 2009-07-05
- Posts: 2
Remainder Theorem/Factor Theorem/Partial Fractions Question
A cubic equation f(x) = 0 has roots -3, -1 and 4. f(x) leaves a remainder of 12 when it is divided by x+2. Find the remainder when f(x) is divided by x^2 -2x-1.
Answer is -16x - 20.
Please assist. I think there's long division involved, but I'm just making assumptions.
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#2 2009-07-05 20:44:12
- Identity
- Member
- Registered: 2007-04-18
- Posts: 934
Re: Remainder Theorem/Factor Theorem/Partial Fractions Question
The cubic equation can be written as:
Since if you sub in the roots of x you get zeros.
Now use the remainder theorem to find the value of a, and long divide for the final answer.
Last edited by Identity (2009-07-05 20:44:27)
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