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17 vote

Which one of the following is a factor of x3 + 5x + 18?

Asked on by | Votes 17 | Views: 94 | Tags: algebra     | quantitative aptitude     | Add Bounty

Which one of the following is a factor of x3 + 5x + 18?


1). x - 2
2). x + 2
3). x - 1
4). x + 1


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1 answers

39 vote
Answered by on | Votes 39 |

If x - a is a factor of x3 + 5x + 18

Then value of a3 + 5a + 18 will be zero

First we substitute x = 2

(2)3 + 5(2) + 18 = 36 ≠ 0

Now x = -2

(-2)3 + 5(-2) + 18 = 0

So this is a solution of equation and (x + 2) is a root of this polynomial

Next if we check the remaining options no one will satisfy the polynomial

Accepted Answer

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