You should know the following:[br][br][list][*]A quadratic is normally given in one of three forms:[br] [color=#ff7700][/color][math]ax^2+bx+c[/math][color=#ff7700] (expanded / normal form)[br] [math]\left(x+p\right)\left(x+q\right)[/math] (factorised form)[br][/color] [math]A\left(x+B\right)^2+C[/math] (completed square form)[/*][*]The quadratic formula, [math]x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}[/math], can be used to find the solution(s) to [b]any[/b] quadratic equation (if it has any), and [u][color=#ff0000]must be learned off by heart[/color][/u].[/*][*]The discriminant, [math]b^2-4ac[/math], indicated the number of roots: [math]>0[/math] means [b]two[/b] roots; [math]=0[/math] means [b]one [/b]root; [math]<0[/math] means [b]no[/b] real roots.[/*][/list][br][br]Use the Step-by-Step tool below to walk through the steps for completing the square of any quadratic expression.