A quadratic equation is an equation that looks like this:
ax2+bx+c=0
where a, b, and c are numbers, called coefficients. For example:
x2+3x+4=0
You can think about a quadratic equation in terms of a graph of a
quadratic function. The equation means that you have to find the
points on the horizontal axis x where the graph intersects
with the axis.
To solve a quadratic equation, you have to calculate a number
called discriminant, usually denoted as d:
d=b2−4ac
Depending on the value of d, there are the folowing three possibilities:
Discriminant d is greater than zero. The equation has two solutions:
x=−b±b2-4ac2a
Discriminant is zero. There is only one solution.
x=−b2a
Discriminant is less than zero. No solutions are defined.