InterviewSolution
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InterviewSolution
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The polynomial `P(x)=x^(3)+ax^(2)+bx+c` has the property that the mean of its roots, the product of its roots, and the sum of its coefficients are all equal. If the `y`-intercept of the graph of `y=P(x)` is `2`, The value of `P(1)` isA. `0`B. `-1`C. `2`D. `-2` |
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Answer» Correct Answer - D The `y`-intercept is at `x=0`, so we have `c=2`, meaning that the product of the roots is `-2`. We know that `-a` is the sum of the roots. The average of the roots is equal to the product, so the sum of the roots is `-6`, and `a=6`. Finally, `1+a+b+c=2` as well, so we have `1+6+b+2=-2` `impliesb=-11` `:.P(x)=x^(3)+6x^(2)-11x+2` `:.P(1)=1+6-11+2=-2` |
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