Question

A quadratic equation has exactly one real number solution. Which is the value of its discriminant?

Answer 1

Answer: The determinant must be zero.

Step-by-step explanation:

For a quadratic equation

a*x^2 + b*x + c = 0

The discriminant is:

D = b^2 - 4*a*c

and the solutions can be finded as:

$x = \frac{-b+- \sqrt{D} }{2*a}$

If D > 0 we have two real solutions

if D = 0 we only have one solution, x = -b/2a

If D < 0 we will have comples solutions, as we will have a negative number inside a square root.

Knowing that for this equation we have only one solution, then we can know that the determinant must be equal to zero.