Question 600322: I need help solving a polynomial using synthetic division.
(4x^3-9ix^2+5x+(8-4i))/(x-i)
Thank You Found 2 solutions by stanbon, Edwin McCravy:Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! (4x^3-9ix^2+5x+(8-4i))/(x-i)
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i)....4......9i......5......(8-4i)
.......4......13i....-8.....|..9-12i
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Quotient: 4x^2 + 13ix - 8
Remainder: 9-12i
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cheers,
Stan H.
The other tutor's answer is wrong.
Start with this:
i | 4 -9i 5 8-4i
|__________________
Bring down the 4
i | 4 -9i 5 8-4i
|__________________
4
Multiply the 4 by the i gatting 4i. Write 4i above and to the
right of the 4 that you brought down, underneath the -9i:
i | 4 -9i 5 8-4i
| 4i
4
Add the -9i and the 4i getting -5i. Write that below the line
under the 4i
i | 4 -9i 5 8-4i
| 4i
4 -5i
Multiply the -5i by the i and get -5i², then
replace i² by -1 and get -5(-1) or 5 and write
5 above and to the right of the -5i under the
other 5:
i | 4 -9i 5 8-4i
| 4i 5
4 -5i
Add the 5 and the 5 getting 10 and
write that at the bottom under the
5's
i | 4 -9i 5 8-4i
| 4i 5
4 -5i 10
Multiply the 10 by the i getting 10i.
Write that above and to the right of
the 10 underneath the -4i
i | 4 -9i 5 8- 4i
| 4i 5 10i
4 -5i 10
Add the 8-4i and the 10i getting 8+6i.
Write that at the bottom under the +10i
i | 4 -9i 5 8- 4i
| 4i 5 10i
4 -5i 10 8+ 6i
Use the first three terms on the bottom row
as coefficients of a quadratic equation,
then put the last number on the bottom over
the original divisor x-i
4x² - 5ix + 10 +
Edwin