Help with C1 Maths Edexcel

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    Name:  Screen Shot 2016-10-06 at 17.41.06.png
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Size:  15.4 KBI know that if it has real roots the discriminant must be > 0, but the text book says the answer is < or the same as the value of x, help please?
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     b^2 - 4ac &gt; 0 \\64 - 20k &gt; 0 \\ 20k &lt; 64 \\ k &lt; 16/5 \\ Not sure what your textbook is on about - maybe we are both missing something?
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    (Original post by dfbenjamin)
     b^2 - 4ac &gt; 0 \\64 - 20k &gt; 0 \\ 20k &lt; 64 \\ k &lt; 16/5 \\ Not sure what your textbook is on about - maybe we are both missing something?
    Yeah I don't get why it's equal to - I'lll have to ask my teacher tomorrow
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    (Original post by jessnoch)
    Yeah I don't get why it's equal to - I'lll have to ask my teacher tomorrow
    Oh you mean that you have k<=16/5? I think that's because you can sometimes consider a double root to be 2 roots instead of 1. I thought you meant the answer was k<=x which would be really confusing!
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    (Original post by dfbenjamin)
    Oh you mean that you have k<=16/5? I think that's because you can sometimes consider a double root to be 2 roots instead of 1. I thought you meant the answer was k<=x which would be really confusing!
    Ohhh okay thankyou!
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    (Original post by jessnoch)
    Ohhh okay thankyou!
    No problem - check with your teacher tomorrow anyway since it could be a defined thing in your course that you're assumed to know.
 
 
 
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