Question 1090501
<br>In the quadratic formula, the discriminant, b^2-4ac, tells you whether the quadratic expression has two, one, or no real zeros.  If the discriminant is positive, there are two zeros; if it is 0, there is one zero (a double root); if it is negative, there are no real zeros.<br>
So in your example, there is only one zero if the discriminant is zero:
{{{b^2-4ac = k^2-4(1)(1) = k^2-4 = 0}}}
{{{k^2-4 = 0}}}
{{{(k+2)(k-2) = 0}}}<br>
The values -2 and 2 each make the discriminant equal to 0.<br>
So answer C, -2 and 2.