For the quadratic function (f(x)=ax^2+bx+c), the expression (b^2-4ac) is known as the bdiscriminant/b. The value of the discriminant tells you how many roots (f(x)) has. [ul]liIf (b^2-4ac>0), (f(x)) has two real roots, and (y=f(x)) will cross the x-axis twice.[/li]liIf (b^2-4ac=0), (f(x)) has one repeated root, and (y=f(x)) will touch the x-axis once.[/li]liIf (b^2-4ac<0), (f(x)) has no real roots, and (y=f(x)) will not cross the x-axis.[/li]/ul If the question refers to two/one/no solutions, or graphs intersecting/touching/not intersecting each other, then it is likely that you will need to use the discriminant to do the question.

For the quadratic function (f(x)=ax^2+bx+c), the bdiscriminant/b ((b^2-4ac)) tells you how many roots the function has. ulliIf (b^2-4ac>0), (f(x)) has two real roots.[/li]liIf (b^2-4ac=0), (f(x)) has one repeated root.[/li]liIf (b^2-4ac<0), (f(x)) has no real roots.[/li]/ul