Question

find the value of K if x-1 is a factor of P(x) =x³+2x-k​

Answer 1

If x-1 is a factor of P(x) then,

$P(x)=(x-1)G(x),\:for\:some\:polynomial\:G(x)$

Here, we see that

P(x) = 0 for x = 1

$\implies 1^{3}+2 \times 1-k=0$

$\therefore k=3$