If m, n, and 1 are non-zero roots of the equation [tex]x^3 - mx^2 + nx - 1 = 0[/tex], then find the sum of the roots(adsbygoogle = window.adsbygoogle || []).push({});

This is what I did..

m, n, 1 are the roots. m and n not equal to 0

[tex]x^3 - mx^2 + nx - 1 = 0[/tex]

f(m) = 0 --> m^3 - m^3 + mn - 1

1 = mn (1)

f(1) = 1 - m + n - 1 = 0

... m = n (2)

Sub (2) --> (1)

[tex]m^2 = 1 [/tex]

[tex]m = +/- 1

since m and n are equal... the roots must be either 1, 1, 1 or -1, -1, 1. The answer on the sheet says the answer is -1. So my question is, how do we determine which roots are the answers. Thanks

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# Polynomial Help

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