C1 roots help

I'm doing a past paper and this is the question:

Given that the equation 2qx^2 + qx - 1 = 0, where q is a constant, has no real roots,

a) show that q^2 + 8q < 0 (2 marks)

b) Hence find the set of possible values for q. (3 marks)

I know for no real roots the inequality is b^2 - 4ac < 0, and plugging in the numbers I get q^2 + 8q < 0. How do I find the set of possible values for b?

Well, how would you normally find the values of y such that y^2 + 8y < 0?

(Hint: think about factorizing)

Thanks!