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Find the quotient and remainder using synthetic division for

x
5
-
x
4
+
9
x
3
-
9
x
2
+
9
x
-
10
x
-
1


The quotient is
The remainder is

Find the quotient and remainder using synthetic division for x 5 - x 4 + 9 x 3 - 9 x-example-1
User Payerl
by
8.9k points

1 Answer

5 votes

Explanation:

it follows practically the same rules as a division between plain numbers.

(x⁵ - x⁴ + 9x³ - 9x² + 9x - 10)/(x - 1) = x⁴

we take the first term (x⁵) and divide it by the x term(s) of the divisor (we ignore constants for the moment). the resulting x term : x⁴

as x⁵/x = x⁴

now we multiply the intermediate result with the full divisior and subtract that result from the left side of the dividend :

(x⁵ - x⁴ + 9x³ - 9x² + 9x - 10)/(x - 1) = x⁴

- x⁵ - x⁴

--------------

0 0

now we "pull down" the next term of the dividend and we calculate

(0 + 0 + 9x³) / x = 9x²

so, we have now

(x⁵ - x⁴ + 9x³ - 9x² + 9x - 10)/(x - 1) = x⁴ + 9x²

and we do the same thing as before (multiply intermediate result with divisor and subtract the result)

(x⁵ - x⁴ + 9x³ - 9x² + 9x - 10)/(x - 1) = x⁴ + 9x²

0 0 9x³

- 9x³ - 9x²

---------------

0 0

and, again, we pull down the next term of the dividend abd divide by the x term(s) of the divisor

(0 + 0 + 0 + 0 + 9x) / x = 9

so, we have now

(x⁵ - x⁴ + 9x³ - 9x² + 9x - 10)/(x - 1) = x⁴ + 9x² + 9

and we do the same thing as above again

(x⁵ - x⁴ + 9x³ - 9x² + 9x - 10)/(x - 1) = x⁴ + 9x² + 9

- 0 0 0 0 9x - 9

-----------

0 - 1

since we ran out of additional terms, we are finished.

the quotient is

x⁴ + 9x² + 9

the remainder is

-1

which makes the full division result

(x⁵ - x⁴ + 9x³ - 9x² + 9x - 10)/(x - 1) =

= x⁴ + 9x² + 9 - 1/(x - 1)

let's check :

(x⁴ + 9x² + 9 - 1(x - 1)) × (x - 1) =

= x⁵ + 9x³ + 9x - x⁴ - 9x² - 9 - 1 =

= x⁵ - x⁴ + 9x³ - 9x² + 9x - 10

perfect.

User Stephenye
by
7.9k points

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