hi i've got a question i'd like some help with:

given that P(x), where $\displaystyle P(x) = x^3 + 3x^2 + kx + 4$ and k is a constant, is such that the remainder on dividing P(x) by $\displaystyle (x - 1)$ is three times the remainder on dividing P(x) by (x + 1), find the value of k

could someone show me the steps to do this please? thankyou