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Maths question help

Given that the equation,
- kx + 5 = 0, k>0 has equal roots. Find the value of k in the form a√b where a and b are integers. (4)can anyone please give me a step by step tutorial on how to solve this question.
Thank you
Help given, edited to remove full solution as it's against the rules
(edited 7 years ago)
Reply 2
Original post by Swifty139
Given that it has equal roots, you should know that the discriminant; b^2 - 4ac, is equal to 0.

Quadratics are in the form ax^2 + bx + c = 0, so in this case we have a=1, b=-k and c=5. Therefore using our equation:

(-k)^2 - 4(1)(5) = 0

k^2 - 20 = 0

k^2 = 20

k = root20

k = 2root5

Oh I just found it difficult due to the wording in the question, but thank you very much now i understand the concept. I appreciate you giving me a step by step solution on how to solve this problem :smile:
Original post by Swifty139
Given that it has equal roots, you should know that the discriminant; b^2 - 4ac, is equal to 0.

Quadratics are in the form ax^2 + bx + c = 0, so in this case we have a=1, b=-k and c=5. Therefore using our equation:

(-k)^2 - 4(1)(5) = 0

k^2 - 20 = 0

k^2 = 20

k = root20

k = 2root5


Don't post full solutions.
Original post by RDKGames
Don't post full solutions.


Why not? :s-smilie: Is there some rule i'm unaware of?
Original post by Swifty139
Why not? :s-smilie: Is there some rule i'm unaware of?


It's against the forum rules. Refer to the stickies at the top of the forum.

http://www.thestudentroom.co.uk/showthread.php?t=4066671&p=64637319#post64637319
(edited 7 years ago)

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