How do you find the discriminant of x^2-2x+1=0x22x+1=0 and use it to determine if the equation has one, two real or two imaginary roots?

1 Answer
May 13, 2017

Delta =0 -> equation has a one real solution x=1

Explanation:

Consider the general form of the quadratic equation:

ax^2+bx+c=0

The discriminant (Delta) is defined as: b^2-4ac

Three cases arise:

(i) Delta >0 -> the equation has two distinct real roots
(ii) Delta <0 -> the equation has two complex roots
(iii) Delta =0 -> the equation has one real solution (Strictly, two equal real roots)

In our equation: x^2-2x+1=0

Delta = (-2)^2-4*1*1 = 4-4 =0

Hence the equation has one real solution.

The equation may be factorised as: (x-1)(x-1)=0

Hence the only real solution is x=1