How do you divide (3x^4+22x^3+ 15 x^2+26x+8)/(x-2) 3x4+22x3+15x2+26x+8x2?

1 Answer
Dec 28, 2015

Long divide the coefficients to find:

(3x^4+22x^3+15x^2+26x+8)/(x-2) = 3x^3+28x^2+71x+1683x4+22x3+15x2+26x+8x2=3x3+28x2+71x+168

with remainder 344344

Explanation:

There are other ways, but I like to long divide the coefficients like this:

enter image source here

A more compact form of this is called synthetic division, but I find it easier to read the long division layout.

Reassembling polynomials from the coefficients, we find:

(3x^4+22x^3+15x^2+26x+8)/(x-2) = 3x^3+28x^2+71x+1683x4+22x3+15x2+26x+8x2=3x3+28x2+71x+168

with remainder 344344.

Or you can write:

3x^4+22x^3+15x^2+26x+83x4+22x3+15x2+26x+8

= (x-2)(3x^3+28x^2+71x+168) + 344=(x2)(3x3+28x2+71x+168)+344

Note that if you are long dividing polynomials that have a 'missing' term, then you need to include a 00 for the coefficient of that term. We don't need to do that for our example.

As a check, let f(x) = 3x^4+22x^3+15x^2+26x+8f(x)=3x4+22x3+15x2+26x+8 and evaluate f(2)f(2), which should be the remainder:

f(2) = 3*16+22*8+15*4+26*2+8f(2)=316+228+154+262+8

=48+176+60+52+8=48+176+60+52+8

=344=344