Quadratic formula is used in solving the quadratic equation of the form ax2 + bx + c = 0. This equation is derived from the mathematical technique called "completing the square". By substituting the attributes a, b and c, quadratic equation can be found.
A quadratic equation is one with the form ax2+bx+c where a is not equal to 0. If a is equal to 0, then it is said to be a linear equation.