To find the x intercepts of a quadratic function, means to find those values of x for which y equals zero, graphically, it implies to find the values that pass through the x axis.
There is a standar formula to apply whenever you have to find those vaues. Consider you have the following quadratic function: [tex]y=f(x)=ax^2+bx+c[/tex], where "a" is the coefficient of the quadratic term, "b" is the coefficient of the linear term in your equation, and "c" is the y intercept (the value of y when x equals zero).
Then the x intercepts can be obtained applying the following formula: [tex]\frac{-b(+-)\sqrt{b^2-4ac} }{2a}[/tex].
Remember that the letters a, b and c are the coefficients in your equation.
You always obtain two intercepts, because of the (+-) in the formula: [tex]x_1=\frac{-b+\sqrt{b^2-4ac} }{2a}[/tex] and [tex]x_2=\frac{-b-\sqrt{b^2-4ac} }{2a}[/tex].
If the equation is [tex]y=3x^2-4x-2[/tex], then a=3, b= -4 and c= -2.
