Discriminant and Nature of Roots of a Quadratic Equation

What is the formula in getting the discriminant of a quadratic equation?

If the discriminant is equal to -7, the nature of roots of quadratic equation is ____.

• 
  real and equal

• rational and unequal

• irrational and unequal

• no real roots

• 
  real and equal

• rational and unequal

• irrational and unequal

• no real roots

If the discriminant is equal to 400, the nature of roots of the quadratic equation is ____.

• 
  real and equal

• rational and unequal

• irrational and unequal

• no real roots

The roots of a quadratic equation are real and equal, then the discriminant is ____.

• 
  Zero

• Positive and a perfect square

• Positive but not a perfect square

• Negative

• 
  128

• 64

• 0

• -64

• 
  real and equal

• rational and unequal

• irrational and unequal

• no real roots

• -44

• 44

• 52

• -52

What is the discriminant if a = 2, b = -6 and c = -8?

• -100

• 100

• -196

• 196

What is the nature of roots if a = 2, b= -3 and c = 4?

• real and equal

• rational and unequal

• irrational and unequal

• no real roots