Thread: Can someone help me with this pre-Calculus question?

If 2x^2-dx+(31-d^2)x+5 has a factor of x - d, what is the value of d if d is an integer?

Hint:

Write in standard form:



Now, use the rational roots theorem to see if this cubic has any integral roots.

Small missing step: If x-a is a factor of a polynomial P(x), then P(a) = 0 (Remainder theorem).

Salahuddin
Maths online

That missing step was given in a duplicate post in another forum. I didn't feel it necessary to repeat it, but rather continued the discussion here after he was asked to post in an appropriate forum.