Find all positive values for k for which each of the following can be factored.
X^2-x-k
(Your answer seems to be the same as the other problem x^2+x-k )
Is this correct too?
Consider your equation to be in the form ax^2 + bx = c = 0. It can be factored (that is, have real answers for x) if the term b^2 - 4ac is positive or zero. In your case,
b^2 - 4ac = 1 + 4k, so 1+4k >or= 0
k >or= -1/4
If k = -1/4, you have the special case
(x-1/2)^2 = 0, with only one root, x = 1/2