How do you use synthetic division to divide (x^3-729)/(x-9)x3729x9?

1 Answer
Jan 23, 2017

Quotient is x^2+9x+81x2+9x+81 and remainder is 00.

Explanation:

To divide x^3-729x3729 or x^3+0x^2+0x-729x3+0x2+0x729 by x+2x+2

One Write the coefficients of xx in the dividend inside an upside-down division symbol.

color(white)(1)|color(white)(X)1" "color(white)(X)0color(white)(XX)0" "" "-7291X1 X0XX0 729
color(white)(1)|" "color(white)(X)1 X
" "stackrel("—————————————)

Two As x-9=0 gives x=9 put 9 at the left.

9color(white)(X)|1" "color(white)(X)0color(white)(XX)0" "" "-729
color(white)(xx)|" "color(white)(XX)
" "stackrel("—————————————)

Three Drop the first coefficient of the dividend below the division symbol.

9color(white)(X)|1" "color(white)(X)0color(white)(XX)0" "" "-729
color(white)(xx)|" "color(white)(X)
" "stackrel("—————————————)
color(white)(xx)|color(white)()color(red)1

Four Multiply the result by the constant, and put the product in the next column.

9color(white)(X)|1" "color(white)(X)0color(white)(XX)0" "" "-729
color(white)(xx)|" "color(white)(Xx)9
" "stackrel("—————————————)
color(white)(xx)|color(white)()color(blue)1

Five Add down the column.

9color(white)(X)|1" "color(white)(X)0color(white)(XX)0" "" "-729
color(white)(xx)|" "color(white)(Xx)9
" "stackrel("—————————————)
color(white)(xx)|color(white)()color(blue)1color(white)(xxx)color(red)9

Six Repeat Steps Four and Five until you can go no farther.

9color(white)(X)|1" "color(white)(X)0color(white)(XX)0" "" "-729
color(white)(xx)|" "color(white)(Xx)9color(white)(XX)81color(white)(XXxx)729
" "stackrel("—————————————)
color(white)(xx)|color(white)()color(blue)1color(white)(xxx)color(red)9color(white)(XX)color(red)81color(white)(XXXXX)color(red)0

Hence, Quotient is x^2+9x+81 and remainder is 0.