Quadratic Equation Solver

If you have an equation of the form "ax² + bx + c = 0", we can solve it for you. Just enter the factors a, b and c below, and press "Get Results"


a	b	c
x² +	x +		= 0

Your Equation:
Solution 1:
Solution 2:
Discriminant:
Note:

Is it Quadratic?

Only if it can be put in the form ax² + bx + c = 0, and a is not zero.

The name comes from "quad" meaning square, So, the biggest clue is that highest power must be a square (in other words x²).

These are all quadratic equations in disguise:

In disguise	In standard form	a, b and c
x² = 3x -1	x² - 3x + 1 = 0	a=1, b=-3, c=1
2(x² - 2x) = 5	2x² - 4x - 5 = 0	a=2, b=-4, c=-5
x(x-1) = 3	x² - x - 3 = 0	a=1, b=-1, c=-3
5 + 1/x - 1/x² = 0	5x² + x - 1 = 0	a=5, b=1, c=-1

How does this work?

The solution(s) to a quadratic equation can be calculated using the Quadratic Formula:

The "±" means you need to do a plus AND a minus, and therefore there are normally TWO solutions !

The blue part (b² - 4ac) is called the "discriminant", because it can "discriminate" between the possible types of answer. If it is positive, you will get two normal solutions, if it is zero you get just ONE solution, and if it is negative you get imaginary solutions.