Alpha and beta roots help (1 Viewer)

[blacksriders]

For what value of k will thee equation x^2 - (k+2)x + (k-4) = 0 have ..

one root equal to zero ?

 

[Trebla]

If one root equals zero, then the constant must the zero i.e.
k - 4 = 0
=> k = 4

 

[blacksriders]

What if one of the root was = 4 ?

 

[Timothy.Siu]

What if one of the root was = 4 ?

x^2 - (k+2)x + (k-4) = 0

a+b=k+2
ab=k-4
if a=4
4+b=k+2 and 4b=k-4
b=k-2 sub into the other one
4k-8=k-4
3k=4
k=4/3
(doesn't look right)

 

[Trebla]

What if one of the root was = 4 ?

Is this a separate question? If it is, just sub x = 4 into the equation and solve for k.

 

[Timothy.Siu]

Is this a separate question? If it is, just sub x = 4 into the equation and solve for k.

or that, much easier, silly me