The curves of the quadratic and cubic functions are f(x)=2x-x^2
and g(x)= ax^3 +bx^2+cx+d. where a,b,c,d ER, intersect at 2 points
P and Q. These points are also two points of tangency for the two
tangent lines drawn from point A(2,9) upon the parobala. The graph
of the cubic function has a y-intercept at (0,-1) and an x
intercept at (-4,0). What is the value of the coefficient "b" in
the equation of the given cubic function.