The function f is defined by f(x)=2x^3-x^2+kx-6, where k is a constant. In the xy-plane, the graph of f intersects the x-axis at the three points (3,0), (-1/2,0), and (q,0). What is the value of k?

Answer 1

take the first equaitions.
0=2*27-9+3k-6
or
-3k=54-9-6
3k=-39
k=-13