How do I find the x-intercepts of the graph of y=x^2-11x+18?

To find the x-intercepts of the graph of ##y=x^2-11x+18## substitute 0 for y and solve for x.
##0=x^2-11x+18##
Now factor the quadratic expression on the right.
##0=(x-2)(x-9)##
and set each factor equal to 0 and solve.
##(x-2)=0## or ##(x-9)=0## ##=>x=2## or ##x=9##
The x-intercepts of any function ##y = f(x)## are found
by setting ##f(x)=0## since the y-coordinate of any point on the
x-axis is zero.
See image below.