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Mathematics 23 Online
OpenStudy (waheguru):

Question for quadratics

OpenStudy (waheguru):

hartnn (hartnn):

express that equation as ax^2+bx+c =0 use b^2-4ac =0

OpenStudy (waheguru):

How can I even make this in the standard form?

hartnn (hartnn):

expand left side and right side.

OpenStudy (waheguru):

Can i cross out the (x-1) on both sides?

OpenStudy (waheguru):

|dw:1381606517565:dw|

hartnn (hartnn):

yes, sure.

OpenStudy (waheguru):

how how can I set it in standard from?

hartnn (hartnn):

let me try without cancelling...

hartnn (hartnn):

i am getting imaginary values of k :O

hartnn (hartnn):

@ganeshie8 any thoughts?

ganeshie8 (ganeshie8):

thinking... @phi

ganeshie8 (ganeshie8):

we wanto prove , D = 0 ?

hartnn (hartnn):

x=1 satisfies the equation, but the value of k....... ?

hartnn (hartnn):

i guess we need to prove D=0 for only one value of k

ganeshie8 (ganeshie8):

it seems tricky lol..

hartnn (hartnn):

let me try again, kx^2-k = x^2-2x+1 (k-1)x^2 +2x + (-k-1) = 0 oh, i got my error.

ganeshie8 (ganeshie8):

i got d same wats wrong wid that hnmm

hartnn (hartnn):

damn 4 = -4 (k-1) (k+1) -1 = k^2-1 k^2=0 yup, the only value of k is 0

ganeshie8 (ganeshie8):

damn yes k=0 is the oly value of k ugh

hartnn (hartnn):

let me write all steps together., for that equation to have only one solution, D = 0 kx^2-k = x^2-2x+1 (k-1)x^2 +2x + (-k-1) = 0 a=k-1, b=2 , c= -k-1 b^2=4ac 4 = 4 (k-1) (-k-1) 4 = -4 (k-1) (k+1) -1 = k^2-1 k^2=0 k= 0 is the only value of k.

OpenStudy (waheguru):

thank you for your help guys

OpenStudy (waheguru):

(k-1)x^2 +2x + (-k-1) = 0 How did you get that @hartnn

hartnn (hartnn):

kx^2-k = x^2-2x+1 kx^2 -x^2 +2x -k-1 = 0 subtracting x^2-2x+1 from both sides...

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