Question

The discriminant of the quadratic equation $x^2 + x - 1 = 0$ will be

• A. -4
• B. -5
• C. 4
• D. 2

Hint:

Discriminant helps determine the nature of roots: - $D>0$: two distinct real roots - $D = 0$: equal real roots - $D<0$: imaginary roots

Answer 1

The Correct Option is C

Step 1: Recall the formula for discriminant.
For any quadratic equation $ax^2 + bx + c = 0$, \[ D = b^2 - 4ac \] Step 2: Substitute the values.
Here, \(a = 1, b = 1, c = -1\). \[ D = (1)^2 - 4(1)(-1) = 1 + 4 = 5 \] Step 3: Conclusion.
Therefore, the discriminant is \(D = 5\).