SOLUTION: I need help with this question Use synthetic division to find the remainder (x3-3x+10 divide (x-2)

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Question 129815: I need help with this question
Use synthetic division to find the remainder
(x3-3x+10 divide (x-2)

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

Let's simplify this expression using synthetic division


Start with the given expression %28x%5E3+-+3x+%2B+10%29%2F%28x-2%29

First lets find our test zero:

x-2=0 Set the denominator x-2 equal to zero

x=2 Solve for x.

so our test zero is 2


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 1x%5E3 to -3x%5E1 there is a zero coefficient for x%5E2. This is simply because x%5E3+-+3x+%2B+10 really looks like 1x%5E3%2B0x%5E2%2B-3x%5E1%2B10x%5E0
2|10-310
|

Start by bringing down the leading coefficient (it is the coefficient with the highest exponent which is 1)
2|10-310
|
1

Multiply 2 by 1 and place the product (which is 2) right underneath the second coefficient (which is 0)
2|10-310
|2
1

Add 2 and 0 to get 2. Place the sum right underneath 2.
2|10-310
|2
12

Multiply 2 by 2 and place the product (which is 4) right underneath the third coefficient (which is -3)
2|10-310
|24
12

Add 4 and -3 to get 1. Place the sum right underneath 4.
2|10-310
|24
121

Multiply 2 by 1 and place the product (which is 2) right underneath the fourth coefficient (which is 10)
2|10-310
|242
121

Add 2 and 10 to get 12. Place the sum right underneath 2.
2|10-310
|242
12112

Since the last column adds to 12, we have a remainder of 12. This means x-2 is not a factor of x%5E3+-+3x+%2B+10
Now lets look at the bottom row of coefficients:

The first 3 coefficients (1,2,1) form the quotient

x%5E2+%2B+2x+%2B+1

and the last coefficient 12, is the remainder, which is placed over x-2 like this

12%2F%28x-2%29



Putting this altogether, we get:

x%5E2+%2B+2x+%2B+1%2B12%2F%28x-2%29

So %28x%5E3+-+3x+%2B+10%29%2F%28x-2%29=x%5E2+%2B+2x+%2B+1%2B12%2F%28x-2%29

which looks like this in remainder form:
%28x%5E3+-+3x+%2B+10%29%2F%28x-2%29=x%5E2+%2B+2x+%2B+1 remainder 12


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