A cubic polynomial has x=-3 as one of its roots and y-intercept 9. If the graph passes through (-2,3) and (1,16), find the equation of the polynomial.:rolleyes:

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- August 9th 2007, 12:28 PMpolymeraseadvanced functions
A cubic polynomial has x=-3 as one of its roots and y-intercept 9. If the graph passes through (-2,3) and (1,16), find the equation of the polynomial.:rolleyes:

- August 9th 2007, 02:16 PMgalactus
You can use the given info to build a system and then solve for the coefficients.

The y-intercept is 9, therefore, x=0:

A root is -3:

Passes through (-2,3):

Passes through (1,16):

Now, you have 4 equations with 4 unknowns:

Solve the system and you get:

Therefore, the polynomial is:

This is one way to approach these. Perhaps try this on your other post regarding the quartic.