# Math Help - remainder theorem question - how to get started

1. ## remainder theorem question - how to get started

the question is x^3 + kx + 5 is divided by x-2, the remainder is 3. Use the remainder theorem to find the value of k.

These are my thoughts so far.
(x-2) is not a factor (obviously) - so how is it of any use?

How can I use this information to help find the value of k???

2. Originally Posted by angypangy
the question is x^3 + kx + 5 is divided by x-2, the remainder is 3. Use the remainder theorem to find the value of k.

These are my thoughts so far.
(x-2) is not a factor (obviously) - so how is it of any use?

How can I use this information to help find the value of k???
remainder theorem says f(2) = 3

3. $f(x) = x^3 + kx + 5$, we are told that $f(2) = 3$.

$f(2) = 3 \Rightarrow 8+2k+5 = 3 \Rightarrow 13+2k = 3.$