Date: Thu, 21 Jan 1999 17:00:26 -0600

Hi my name is Eric and I m in 8th Grade honors math (middle) and I'd like to know how to prove the quadratic formula -bħsqrt of b(a)(c)over 2(a)

Hi Eric,

The standard way to derive the general quadratic formula is to "complete the square". Here is an example.


First divide by the coefficient of x squared

To complete the square add, to both sides, the square of half the coefficient of x.




To derive the formula consider the equation

and go through the same steps as in the example


Go to Math Central

To return to the previous page use your browser's back button.