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smc

algebra senior

Problem

Two parabolas have equations and , where and are integers, each chosen independently by rolling a fair six-sided die. What is the probability that the parabolas will have at least one point in common?
(A)
(B)
(C)
(D)
Solution
Set the two equations equal to each other: . Now remove the x squared and get 's on one side: . Now factor : . If cannot equal , then there is always a solution, but if , a in chance, leaving a out , always having at least one point in common. And if , then the only way for that to work, is if , a in chance, however, this can occur ways, so a in chance of this happening. So adding one thirty sixth to , we get the simplified fraction of ; answer .
Final answer
D