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The integer k is selected at random from the set of ten integers {0, 1, 2, ..., 9}.  What is the probability that the equation x^2 + 3x + k = 0 has real roots?

 May 26, 2020
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For real roots the disciminat has to be positive

 

b2-4ac>0        3^2-4(1)(k) > 0

9-4k>0

4k > 9

k > 9/4       so from the list   0- 9 is ten numbers of which 3-9 will result in real roots      7/10

 

 

 

 

 

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 May 26, 2020

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