Question

A third degree polynomial has a real root at 4, a double real root at -1 and passes the point (-6,12). How can I find the equation for the function? I forgot how to do this, please explain!

Answer 1

ok... so use the zeros 1st to find the linear factors... can you do that

Answer 2

(x-4) and (x+1). then use foil?

Answer 3

well close... you have a double zero so

\[P(x) = a(x -4)(x + 1)^2\]

now substitute the point to find a, then you can expand to get the equation.

Answer 4

oh, okay thank you.