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Find the largest integer k such that the equation

5x^2 - kx + 8 = 4x^2

has no real solutions.

 Feb 2, 2021
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5x^2  -kx  +  8   = 4x^2

 

x^2  -kx  + 8    =0

 

If  this has no real solutions, the discriminant  < 0

 

So

 

k^2  - 4*8   <   0

 

k^2   < 32

 

k <    [ sqrt (32)  ]   = 

 

k <   5.66

 

5 is the largest integer   

 

 

cool cool cool

 Feb 2, 2021
edited by CPhill  Feb 2, 2021

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