Which is a factor of f of x is equal to 60 x to the 4th power plus 86 x cubed minus 46 x squared minus 43 x plus 8 ? Use the Rational Root Theorem to help you find your answer.
Answer
A
5 x minus 8
B
x minus 6
C
8 x plus 5
D
6 x minus 1
Explanation
By the Factor Theorem, 6x − 1 is a factor if f(1/6) = 0. Substituting x = 1/6 gives 60/1296 + 86/216 − 46/36 − 43/6 + 8 = 0. Therefore, the factor is 6x − 1, choice A.
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