What is the discriminant of 4/3x^2 - 2x + 3/4 = 0 and what does that mean?

1 Answer
Jul 16, 2015

The discriminant is zero. It tells you that there are two identical real roots to the equation.

Explanation:

If you have a quadratic equation of the form

ax^2+bx+c=0

The solution is

x = (-b±sqrt(b^2-4ac))/(2a)

The discriminant Δ is b^2 -4ac.

The discriminant "discriminates" the nature of the roots.

There are three possibilities.

  • If Δ > 0, there are two separate real roots.
  • If Δ = 0, there are two identical real roots.
  • If Δ <0, there are no real roots, but there are two complex roots.

Your equation is

4/3x^2 – 2x +3/4 = 0

Δ = b^2 – 4ac = (-2)^2 -4×4/3×3/4 = 4 – 4 = 0

This tells you that there are two identical real roots.

We can see this if we solve the equation.

4/3x^2 – 2x +3/4 = 0

16x^2 -24x +9 = 0

(4x-3)(4x-3) = 0

4x-3 = 0 and 4x -3 = 0

4x = 3 and 4x = 3

x = 3/4 and x = 3/4

There are two identical roots to the equation.