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# C2 Polynomial Question watch

1. Hi, i am trying to comprehend a C2 polynomial question where they have given me an equation and are asking me to factorise.

The question reads "Factorise 2x3 + x2 - 18x - 9"

According to the book, i am supposed to sub in -1, 1, 2 ,3 until i find f(p) = 0 so that i can successfully find the factor to the equation.

My question is, is this trial and improvement method the quickest way of finding what the factor is?

Thank you!!
2. (Original post by JamesNeedHelp2)
My question is, is this trial and improvement method the quickest way of finding what the factor is?

Thank you!!
Mostly, yes. Sometimes by looking at the coefficients you can figure out quickly if 1 or -1 would work. Maybe even with +-2. But with higher integers you really need to do the calculations.
3. (Original post by SamKeene)
Mostly, yes. Sometimes by looking at the coefficients you can figure out quickly if 1 or -1 would work. Maybe even with +-2. But with higher integers you really need to do the calculations.
Thank you sir.
4. You only need to check factors of 9 as solutions, so 2 is not worth checking as it doesn't divide 9.
5. (Original post by james22)
You only need to check factors of 9 as solutions, so 2 is not worth checking as it doesn't divide 9.
Appreciated, that way i can focus on numbers that are more likely to be the factor. Thanks!

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