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Math Help - real and imaginary solutions

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    real and imaginary solutions

    find all real and imaginary solutions of f(x) = x^3 + x^2 + 13x -15
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    Quote Originally Posted by kenzie103109 View Post
    find all real and imaginary solutions of f(x) = x^3 + x^2 + 13x -15
    You should be able to see that f(1) = 1^3 + 1^2 + 13(1) - 15 = 0.

    So by the remainder and factor theorems, that means x - 1 is a factor.

    By using long division:

    x^3 + x^2 + 13x - 15 = (x - 1)(x^2 + 2x + 15).


    Now use the Quadratic Formula on the Quadratic factor to find the imaginary solutions.
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