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Polynomials, SMB-011

`g(x)=(x-1)(x^2-2x+8)`.

Justify that `g(x)` only has one zero.  (2 marks)

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`text{Proof (See worked solutions)}`

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`g(x)=(x-1)(x^2-2x+8)`.

`g(1)=0\ \ =>\ \ text{one zero at}\ \ x=1`

`text{Consider the roots of}\ \ y=x^2-2x+8`

`Δ = b^2-4ac=(-2)^2-4*1*8=-28<0`

`text{Since}\ \ Δ<0\ \ =>\ \ text{No zeros (roots)}`

`:. g(x)\ text{only has 1 zero}`

Filed Under: Polynomials Tagged With: num-title-ct-patha, smc-4242-10-Factor Theorem, smc-4242-50-Discriminant

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