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# Synthetic Division question watch

1. Express f(x)=2x^3+5x^2+x-2 in fully factorised form.

So this is my working:

But the answer should be f(x)=(x+1)(x+2)(2x-1). What did I do wrong?
2. (Original post by Airess3)
Express f(x)=2x^3+5x^2+x-2 in fully factorised form.

So this is my working:

But the answer should be f(x)=(x+1)(x+2)(2x-1). What did I do wrong?
You're going to have to post the rest of your working. Can't make sense of that as it stands.
3. (Original post by ghostwalker)
You're going to have to post the rest of your working. Can't make sense of that as it stands.
That's all my working, I put the numbers into the synthetic division from the equation f(x)=2x^3+5x^2+x-2
4. (Original post by Airess3)
That's all my working, I put the numbers into the synthetic division from the equation f(x)=2x^3+5x^2+x-2
OK, so where do you get the top line of "2 5 -4" from? I can't see how it relates to your polynomial.
5. (Original post by Airess3)
Express f(x)=2x^3+5x^2+x-2 in fully factorised form.

So this is my working:

But the answer should be f(x)=(x+1)(x+2)(2x-1). What did I do wrong?
Are you given any factors to begin with?

My approach would be to try some small numbers like +1 and -1 and see if f(1) = 0 or f(-1) = 0. Having done this you can then divide by the appropriate linear factor and reduce the problem to factorizing a quadratic.

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