• November 3rd 2008, 10:43 AM
db5vry
Given that the equation below has equal roots, find the value of k:

kx² - 4x + k - 3 = 0

I've never seen this before. how would it be done?
• November 3rd 2008, 10:46 AM
Moo
Hello,
Quote:

Originally Posted by db5vry
Given that the equation below has equal roots, find the value of k:

kx² - 4x + k - 3 = 0

I've never seen this before. how would it be done?

Do you know about the discriminant $\Delta$ ?

If $\Delta>0$, then there are 2 distinct real roots.
If $\color{red} \Delta=0$, then there are 2 equal real roots (and the polynomial is proportional to a perfect square)
If $\Delta <0$, then there is no real root.

In a polynomial ax²+bx+c, the discriminant $\Delta=b^2-4ac$