Please help quick question on C1

Original post by Farmerjj

Given that x² + 8kx +k =0 has equal roots

Find the value of K

I put it into b² - 4ac and so now have (8k)² - 4K = 0
What do I do next?

now solve that mofo

Reply 2

Make K the subject of the formula after applying the squared on 8k. giving you 64k^2 - 4k = 0 . Try and work from there

Reply 3

Original post by the bear

now solve that mofo

How

Reply 4

Original post by Shady778

Make K the subject of the formula after applying the squared on 8k. giving you 64k^2 - 4k = 0 . Try and work from there

Nope no idea sorry I don't see how you can get an answer from that

Reply 5

Notnek

Original post by Farmerjj

How

If you expand it then you've got a quadratic equation that can be solved by factorising.

It's similar to how you would solve something like

x^2-4x=0

. How would you solve this?

Reply 6

Original post by notnek

If you expand it then you've got a quadratic equation that can be solved by factorising.

It's similar to how you would solve something like

x^2-4x=0

. How would you solve this?

You would factorise to (X-2)(X+2)

Reply 7

Original post by Shady778

Make K the subject of the formula after applying the squared on 8k. giving you 64k² - 4k = 0 . Try and work from there

now factorise into two brackets... or you could use the Quadratic Formula ?

Reply 8

Notnek

Original post by Farmerjj

You would factorise to (X-2)(X+2)

No that would be for

x^2-4 = 0

.

For

x^2-4x=0

you should take out a factor of

x

.

For

64k^2 - 4k = 0

, take out a factor of

4k

Reply 9

Original post by the bear

now factorise into two brackets... or you could use the Quadratic Formula ?

Wrong person XD but yes OP do what this person has said

Reply 10

Original post by notnek

No that would be for

x^2-4 = 0

.

For

x^2-4x=0

you should take out a factor of

x

.

For

64k^2 - 4k = 0

, take out a factor of

4k

Cheers man thanks I've got it now, just had a brain dead moment but thanks you

(1/16) is correct?

Reply 11

Original post by the bear

now factorise into two brackets... or you could use the Quadratic Formula ?

Done now cheers bear 🐻

Reply 12

doon98

64k^2-4k=0

k(64k-4)=0

k=0, 64k-4=0
64k=4
k=1/16

so, k=0 and k=1/16

Reply 13

Original post by Shady778

Wrong person XD but yes OP do what this person has said

Reply 14

Original post by Farmerjj

Cheers man thanks I've got it now, just had a brain dead moment but thanks you

(1/16) is correct?

Its partly correct. However you are missing roots.

Reply 15

Original post by doon98

64k^2-4k=0

k(64k-4)=0

k=0, 64k-4=0
64k=4
k=1/16

so, k=0 and k=1/16

complete answers are discouraged :dontknow:

Reply 16