Finding three X values for y=ax^3+bx^2+cx+d
I am trying to solve for the x's for y=ax^3+bx^2+cx+d.
It cuts the y-axis at (0,30). The gradient at this point is -1.
The gradient where x=1, is -17 and the f ``(x) at this point is -10.
I s.t the coordinates given; set f `(x) =-1 and
I think d=30 and c=-1.
So I need to solve for a,b.
I didn't think solving for x would be this tricky? What have I missed?
Theory of equations solution?
these are the numbers for a=2, b=-11, c=-1, d=30. st these into equation
If I do the Rational Roots test then I get
I know the roots are -3/2,5,2 but what does the solution look like with the theory of equations method solving for x1, x2, x3?