How do you divide (-x^4+6x^3+8x+12)/(x^2-3x+9)?

1 Answer
May 17, 2016

Dividing -x^4+6x^3+8x+12 by x^2-3x+9,

the quotient is -x^2+3x+18 and remainder is 35x-150

Explanation:

To divide -x^4+6x^3+8x+12 by x^2-3x+9,

as -x^4/x^2=-x^2.

Now -x^2xx(x^2-3x+9)=-x^4+3x^3-9x^2

Subtracting -x^4+3x^3-9x^2 from -x^4+6x^3+8x+12, we get

(-x^4+6x^3+8x+12)-(-x^4+3x^3-9x^2)=3x^3+9x^2+8x+12

Now in similar way 3x^3+9x^2+8x+12, x^2-3x+9 can go 3x times and remainder will be

3x^3+9x^2+8x+12-3x(x^2-3x+9)

= 3x^3+9x^2+8x+12-3x^3+9x^2-27x

= 18x^2-19x+12

Now in this, x^2-3x+9 goes 18 times and remainder is

18x^2-19x+12-18(x^2-3x+9)=-19x+54x+12-162=35x-150

Hence when we divide -x^4+6x^3+8x+12 by x^2-3x+9, the quotient is -x^2+3x+18 and remainder is 35x-150