SOLUTION: 2x^4 - 8x^2 + 6 divided by 2x + 2

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Question 85751: 2x^4 - 8x^2 + 6 divided by 2x + 2
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Start with the given polynomial %282x%5E4+-+8x%5E2+%2B+6%29%2F%282x%2B2%29

First lets find our test zero:

2x%2B2=0 Set the denominator 2x%2B2 equal to zero
x=-1 Solve for x.

so our test zero is -1


Now set up the synthetic division table by placing the test zero in the upperleft corner and placing the coefficients of the numerator to the right of the test zero.(note: remember if a polynomial goes from 2x%5E4 to -8x%5E2 there is a zero coefficient for x%5E3. This is simply because 2x%5E4+-+8x%5E2+%2B+6 really looks like 2x%5E4%2B0x%5E3%2B-8x%5E2%2B0x%5E1%2B6x%5E0
-1|20-806

Start by bringing down the leading coefficient (it is the coefficient with the highest exponent which is 2)
-1|20-806
2

Multiply -1 by 2 and place the product (which is -2) right underneath 0
-1|20-806
-2
2

Add -2 and 0 to get -2. Place the sum right underneath -2.
-1|20-806
-2
2-2

Multiply -1 by -2 and place the product (which is 2) right underneath -8
-1|20-806
-22
2-2

Add 2 and -8 to get -6. Place the sum right underneath 2.
-1|20-806
-22
2-2-6

Multiply -1 by -6 and place the product (which is 6) right underneath 0
-1|20-806
-226
2-2-6

Add 6 and 0 to get 6. Place the sum right underneath 6.
-1|20-806
-226
2-2-66

Multiply -1 by 6 and place the product (which is -6) right underneath 6
-1|20-806
-226-6
2-2-66

Add -6 and 6 to get 0. Place the sum right underneath -6.
-1|20-806
-226-6
2-2-660

Since the last column adds to zero, we have a remainder of zero. This means 2x%2B2 is a factor of 2x%5E4+-+8x%5E2+%2B+6

Now lets look at the bottom row of coefficients:

The first 4 coefficients (2,-2,-6,6) form the quotient

2x%5E3+-+2x%5E2+-+6x+%2B+6
Notice in the denominator 2x%2B2, the x term has a coefficient of 2, so we need to divide the quotient by 2 like this:
%282x%5E3+-+2x%5E2+-+6x+%2B+6%29%2F2=x%5E3+-+x%5E2+-+3x+%2B+3

So %282x%5E4+-+8x%5E2+%2B+6%29%2F%282x%2B2%29=x%5E3+-+x%5E2+-+3x+%2B+3