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Given that f(x)=5x^2 - 3x + 7 and f(g(x)) = 40 - 11x^2 - 8x^4, find all possible values for the sum of the coefficients in the polynomial function g(x). Thank you to anyone who replies :)

 Sep 11, 2018

Are you sure you have written the equations correctly?  g(x) must be of order 2, so its highest order term is ax2. This means we must have 5a2 = -8   (because 5a2x4 must equal -8x4).  This would make 'a' an imaginary number!

 Sep 12, 2018

Hi Alan. Yes, I am sure I wrtoe the question correctly.

 Sep 12, 2018

Alan is right, the leading coefficient of g(x) must be     \(\sqrt{\frac{8}{5}}\;\;i\)      


We both think that there is a mistake in the question.  

 Sep 13, 2018

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