SOLUTION: Perform divisions 8x^3-6x^2+2x/ 4x+1

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Question 92270: Perform divisions
8x^3-6x^2+2x/ 4x+1

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Start with the given polynomial %288x%5E3+-+6x%5E2+%2B+2x%29%2F%284x%2B1%29

First lets find our test zero:

4x%2B1=0 Set the denominator 4x%2B1 equal to zero

x=-1%2F4 Solve for x.

so our test zero is -1/4


Now set up the synthetic division table by placing the test zero in the upper left corner and placing the coefficients of the numerator to the right of the test zero.(note: remember if a polynomial goes from 2x%5E1 to 0 there is a zero coefficient for x%5E0. This is simply because 8x%5E3+-+6x%5E2+%2B+2x really looks like 8x%5E3%2B-6x%5E2%2B2x%5E1%2B0x%5E0
-1/4|8-620
|

Start by bringing down the leading coefficient (it is the coefficient with the highest exponent which is 8)
-1/4|8-620
|
8

Multiply -1/4 by 8 and place the product (which is -2) right underneath the second coefficient (which is -6)
-1/4|8-620
|-2
8

Add -2 and -6 to get -8. Place the sum right underneath -2.
-1/4|8-620
|-2
8-8

Multiply -1/4 by -8 and place the product (which is 2) right underneath the third coefficient (which is 2)
-1/4|8-620
|-22
8-8

Add 2 and 2 to get 4. Place the sum right underneath 2.
-1/4|8-620
|-22
8-84

Multiply -1/4 by 4 and place the product (which is -1) right underneath the fourth coefficient (which is 0)
-1/4|8-620
|-22-1
8-84

Add -1 and 0 to get -1. Place the sum right underneath -1.
-1/4|8-620
|-22-1
8-84-1

Since the last column adds to -1, we have a remainder of -1. This means 4x%2B1 is not a factor of 8x%5E3+-+6x%5E2+%2B+2x
Now lets look at the bottom row of coefficients:

The first 3 coefficients (8,-8,4) form the quotient

8x%5E2+-+8x+%2B+4

and the last coefficient -1, is the remainder, which is placed over 4x%2B1 like this

-1%2F%284x%2B1%29



Notice the denominator 4x%2B1, the x term has a coefficient of 4, so we need to divide the quotient by 4 like this:
%288x%5E2+-+8x+%2B+4%29%2F4=2x%5E2+-+2x+%2B+1

Putting this altogether, we get:

2x%5E2+-+2x+%2B+1%2B-1%2F%284x%2B1%29

So %288x%5E3+-+6x%5E2+%2B+2x%29%2F%284x%2B1%29=2x%5E2+-+2x+%2B+1%2B-1%2F%284x%2B1%29

which looks like this in remainder form:
%288x%5E3+-+6x%5E2+%2B+2x%29%2F%284x%2B1%29=2x%5E2+-+2x+%2B+1 remainder -1


You can use this online polynomial division calculator to check your work