Question 725933
The x-intercepts are the points where the parabola (the graph of the quadratic function) crosses the x-axis.
The x-axis has the equation {{{y=0}}}, so the x-intercepts have {{{y=0}}} .
You would just have to find their {{{x}}} coordinates by solving the equation
{{{0=x2 - 8x + 12}}} <--> {{{x2 - 8x + 12 = 0}}} ,
but you already know that the solutions are {{{x=2}}} and {{{x=6}}}.
 
Extra:
You know that the function {{{y=x2 - 8x + 12}}} represents a parabola with a vertical axis of symmetry.
The x-intercepts (2,0) and (6,0) are symmetrical with respect to the vertical line that is the axis of symmetry.
The axis of symmetry passes through the midpoint of the segment connecting those x-intercepts, the point (4,0), with
{{{x=(2+6)/2=4}}} .
The equation of the axis of symmetry is {{{x=4}}} .