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# Calculating the possible values of k watch

1. The quadratic equation ×^2 - 4x - 1= 2k(x-5) has two equal roots. Calculate the possible values of k.

Hi I've been struggling to work this out for quite a while, so I would really appreciate any help for solving this.
2. (Original post by Minbbh)
The quadratic equation ×^2 - 4x - 1= 2k(x-5) has two equal roots. Calculate the possible values of k.

Hi I've been struggling to work this out for quite a while, so I would really appreciate any help for solving this.
Put it into the general quadratic form - then what do you know about the value of the discriminant if it has equal roots?
3. (Original post by Muttley79)
Put it into the general quadratic form - then what do you know about the value of the discriminant if it has equal roots?
I have rearranged the equation to
×^2 - 2kx +10k - 4x -1=0
But I'm stuck on how to put it in the quadratic form since there's a lot of variables and I'm not entirely sure what's b is in here.
4. (Original post by Minbbh)
I have rearranged the equation to
×^2 - 2kx +10k - 4x -1=0
But I'm stuck on how to put it in the quadratic form since there's a lot of variables and I'm not entirely sure what's b is in here.
b is the coefficient of x so it might help to collect the terms in a bracket?
5. this is a nasty question, but what you do is gather the -2kx and 4x together (b). put it in bracket and have x as the common factor. the 10k-1 is then the constant (c)
then plug it into the discriminate

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