posted by nick .
The function f is defined by
f(x) = x^3 - x^2 - 4x + 4
The point (a,b) is on the graph of f and the line tangent to the graph at (a,b) passes through the point (0, -8) which is not on the graph of f. Find the values of a and b.
I have no clue how to solve this
I know the derivative of f prime (x) is
3x^2 - 2x - 4 and so (a,b) would be on the derivative line and so would (0, -8) but how do i find (a,b)???