2003 AMC 12B Problems/Problem 20
Contents
Problem
Part of the graph of is shown. What is ?
Solution
Solution 1
Since
It follows that . Also, , so .
Solution 2
Two of the roots of are , and we let the third one be . Then Notice that , so .
Solution 3
Notice that if , then vanishes at and so implies by coefficient, .
Solution 4
The roots of this equation are , letting be the root not shown in the graph. By Vieta, we know that and . Therefore, . Setting the two equations for equal to each other, . We know that the y-intercept of the polynomial is , so . Plugging in for , .
Therefore,
Solution 5
From the graph, we have so . Also from the graph, we have . But we also have from the graph . Summing we get so .
Solution by franzliszt
See also
2003 AMC 12B (Problems • Answer Key • Resources) | |
Preceded by Problem 19 |
Followed by Problem 21 |
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All AMC 12 Problems and Solutions |
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