Given the polynomial, f(x)= x³ + kx² - 2x + 1, and that f(x) is divided x-k the remainder is k, find the possible values of k.​

Respuesta :

Answer:

k=1

Step-by-step explanation:

According to the remainder Theorem, if we have a polynomial then if it divided by (x-a), the remained will be equal to

[tex]f(a)[/tex]

So we know that the factor is

[tex](x - k)[/tex]

So plug in k into the polynomial

[tex]f(k) = k {}^{3} + k(k) {}^{2} - 2(k) + 1 = k[/tex]

[tex]k {}^{3} + k {}^{3} - 2k + 1 = k[/tex]

[tex]2k {}^{3} - 3k + 1 = 0[/tex]

Solve for k.

Using Rational Roots Theorem, one possible root is 1 so we have

[tex]2k {}^{2} + 2k - 1 = 0[/tex]

Since that is irreducible over reals, 1 is our only factor so k=1.