Which Is the demonstration of ∆=b^2-4ac?

Answer 1

You can derive the discriminate by completing the square from the standard quadratic quadratic equation:

Take the standard quadratic equation and complete the square. This should derive the quadratic formula, which includes the discriminate.

Answer 2

This is the discriminant of the quadratic equation.

x = [ -b +/- sqrt(b² - 4ac) ] / 2a