Enter the coefficients a, b, and c for the quadratic equation (ax² + bx + c = 0) to find its real roots.
3
Apply the quadratic formula to the equation ax2 + bx + c = 0 by first evaluating the discriminant and then substituting into the formula to get the roots.
Key formula: x = (-b ± √(b2 - 4ac)) / (2a)
x = (-b ± √(b2 - 4ac)) / (2a)
Example values: a = 1, b = -3, c = 2.
D = b2 - 4ac = (-3)2 - 4·1·2 = 9 - 8 = 1
√D = 1
x = ( -b ± √D ) / (2a) = (3 ± 1) / 2
x = 2
x = 1
If the discriminant is negative there are no real roots; the quadratic has two complex conjugate roots instead.
If a = 0 the equation is linear (bx + c = 0) and not quadratic; solve it as a linear equation using x = -c/b.
A discriminant of zero indicates one repeated real root given by x = -b / (2a); the parabola touches the x-axis at a single point.