Question

What is the discriminant D of the equation? a2−2a+5=0 Enter your answer in the box.

Answer 1

The Discriminant:
D = b² - 4 a c
D = (-2)² - 4 · 1 · 5 = 4 - 20 = - 16
D = - 16 
D < 0 ,  which means that there are no real solutions. The solutions of this equation are complex conjugate numbers.

Answer 2

For a quadratic equation ax^2 + bx + c = 0, the discriminant is given by b^2 - 4ac
Thus for a^2 - 2a + 5 = 0,
a = 1, b = -2 and c = 5
b^2 - 4ac = (-2)^2 - 4(1)(5) = 4 - 20 = -16