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Find (x^3 + x^2 − 20x + 24) divided by (x − 3).

User Jamieb
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1 Answer

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19 votes

Answer: olynomial Long Division

Dividing : x3 + x2 - 20x + 24

("Dividend")

By : x - 3 ("Divisor")

dividend x3 + x2 - 20x + 24

- divisor * x2 x3 - 3x2

remainder 4x2 - 20x + 24

- divisor * 4x1 4x2 - 12x

remainder - 8x + 24

- divisor * -8x0 - 8x + 24

remainder 0

Quotient : x2+4x-8 Remainder: 0

Factoring x2+4x-8

The first term is, x2 its coefficient is 1 .

The middle term is, +4x its coefficient is 4 .

The last term, "the constant", is -8

Step-1 : Multiply the coefficient of the first term by the constant 1 • -8 = -8

Step-2 : Find two factors of -8 whose sum equals the coefficient of the middle term, which is 4 .

-8 + 1 = -7

-4 + 2 = -2

-2 + 4 = 2

-1 + 8 = 7

Observation : No two such factors can be found !!

Conclusion : Trinomial can not be factored

Find roots (zeroes) of : F(x) = x3 + x2 - 23x + 24

See theory in step 1.3

In this case, the Leading Coefficient is 1 and the Trailing Constant is 24.

The factor(s) are:

of the Leading Coefficient : 1

of the Trailing Constant : 1 ,2 ,3 ,4 ,6 ,8 ,12 ,24

Let us test ....

P Q P/Q F(P/Q) Divisor

-1 1 -1.00 47.00

-2 1 -2.00 66.00

-3 1 -3.00 75.00

-4 1 -4.00 68.00

-6 1 -6.00 -18.00

-8 1 -8.00 -240.00

-12 1 -12.00 -1284.00

-24 1 -24.00 -12672.00

1 1 1.00 3.00

2 1 2.00 -10.00

3 1 3.00 -9.00

4 1 4.00 12.00

6 1 6.00 138.00

8 1 8.00 416.00

12 1 12.00 1620.00

24 1 24.00 13872.00

Polynomial Roots Calculator found no rational roots

Answer: x3 + x2 - 23x + 24

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x

Explanation:

User Balaji Kondalrayal
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