Hello,

1. expand the brackets at the LHS of your equation.

2. collect like terms

You'll get:

Now compare this result with the coefficients at the RHS of the given equation:

This is a system of 3 linear equations which could be solved for k, p, q.

(For confirmation only: I've got k = -13, q = 27, p = -35) but you'd better check my calculations!