SOLUTION: Construct a polynomial function with the following properties: third degree, only real coefficients, −1 and 2+i are two of the zeros, y-intercept is −15.

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Question 1198743: Construct a polynomial function with the following properties: third degree, only real coefficients, −1 and 2+i are two of the zeros, y-intercept is −15.
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39620)   (Show Source): You can put this solution on YOUR website!





The multiplication for the polynomial is not yet finished, but letting x=0 allows to find the factor, "a".
Answer by ikleyn(52812)   (Show Source): You can put this solution on YOUR website!
.

        The post by @josgarithmetic is totally wrong,
        so I came to bring you a correct solution. 


 = 

 = 

 = 

 = 

 = 


To find "a", put x=0 in this equation.  You will get

    5a = -15,  a = -15/5 = -3.


So, the polynomial is  -3(x+1)*(x^2-4x+5).    ANSWER

Solved in full and in correct form.


///////////////


He re-wrote his post after seeing my post.




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