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C1 question

Can't believe I'm stuck on this question but yh, need help :l

kx^2 +12x + k =0

k = +ve

and it has equal roots

^ I know this means that both values of x are the same but I have no idea how to do it!
Reply 1
Avatar for steve2005
steve2005
17
Original post by 0range
Can't believe I'm stuck on this question but yh, need help :l

kx^2 +12x + k =0

k = +ve

and it has equal roots

^ I know this means that both values of x are the same but I have no idea how to do it!


Hint b^2 - 4ac = 0
Reply 2
Avatar for zincoff
zincoff
B^2-4ac =

144-4k^2=0

k^2=36

k=6

6x^2+12x+6=0

x^2+2x+1=0

(x+1)^2=0
Reply 3
Avatar for raheem94
raheem94
13
Original post by zincoff
B^2-4ac =

144-4k^2=0

k^2=36

k=6

6x^2+12x+6=0

x^2+2x+1=0

(x+1)^2=0


Please don't post full solutions.

First give hints to the OP, post full solutions as a last resort.
Reply 4
Avatar for 0range
0range
OP
20
Original post by steve2005
Hint b^2 - 4ac = 0


Missed that! Thanks!

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