2005 AMC 12B Problems/Problem 12
Problem
The quadratic equation has roots twice those of , and none of and is zero. What is the value of ?
Solution
Let have roots and . Then
so and . Also, has roots and , so
and and . Thus .
Indeed, consider the quadratics . See Vieta's formulas.
See also
2005 AMC 12B (Problems • Answer Key • Resources) | |
Preceded by Problem 11 |
Followed by Problem 13 |
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All AMC 12 Problems and Solutions |